diff --git a/README.md b/README.md
index 93b3766..8eb273c 100644
--- a/README.md
+++ b/README.md
@@ -7,13 +7,13 @@ On the other hand, `rubocop` has [`--auto-correct`](https://github.com/rubocop-h
 It is ideal that to remove a disabled rule from `.rubocop_todo.yml` every day, to check whether it passes test, and can be obtained consent from the team. But it requires strong persistence and time.
 I call such work *Rubocop Challenge*. And the *RubocopChallenger* is a gem to support this challenge!
 
-## The history of RubocopChallenger with decrease of offence codes
+## The history of RubocopChallenger with decrease of offense codes
 
-The following chart shows the history of RubocopChallenger and decrease of offence codes at a `.rubocop_todo.yml`. The project was released at 5 years ago, and then it was introduced the RuboCop gem for huge source code including a lots of offence codes. Before using the RubocopChallenger, it was not maintain to reduce offence codes. One day, I felt a crisis and started maintain with manual. I made a lots of Pull Requests to reduce them but it's a load for me and reviewers. So I created a script for automation the flow, which is the predecessor of Rubocop Challenger gem. It brought reducing the offence codes continuously. After 8 months, finally it has done. There is no auto-correctable offence codes.
-But there are many offences which is un-auto-correctable yet. I will try to reduce it with the RubocopChallenger. The RubocopChallenger will
+The following chart shows the history of RubocopChallenger and decrease of offense codes at a `.rubocop_todo.yml`. The project was released at 5 years ago, and then it was introduced the RuboCop gem for huge source code including a lots of offense codes. Before using the RubocopChallenger, it was not maintain to reduce offense codes. One day, I felt a crisis and started maintain with manual. I made a lots of Pull Requests to reduce them but it's a load for me and reviewers. So I created a script for automation the flow, which is the predecessor of Rubocop Challenger gem. It brought reducing the offense codes continuously. After 8 months, finally it has done. There is no auto-correctable offense codes.
+But there are many offenses which is un-auto-correctable yet. I will try to reduce it with the RubocopChallenger. The RubocopChallenger will
 be continued to evolve.
 
-![Decrease of offence codes](images/decrease_of_offence_codes.png)
+![Decrease of offense codes](images/decrease_of_offense_codes.png)
 
 ## Rubocop Challenge Flow
 
diff --git a/spec/lib/rubocop_challenger/rubocop/todo_reader_spec.rb b/spec/lib/rubocop_challenger/rubocop/todo_reader_spec.rb
index f72c961..a4b2528 100644
--- a/spec/lib/rubocop_challenger/rubocop/todo_reader_spec.rb
+++ b/spec/lib/rubocop_challenger/rubocop/todo_reader_spec.rb
@@ -5,7 +5,7 @@
 RSpec.describe RubocopChallenger::Rubocop::TodoReader do
   let(:todo_reader) { described_class.new('spec/fixtures/.rubocop_todo.yml') }
 
-  let(:autocorrectable_rule_which_offence_count_is_1) do
+  let(:autocorrectable_rule_which_offense_count_is_1) do
     RubocopChallenger::Rubocop::Rule.new(<<~CONTENTS)
       # Offense count: 1
       # This cop supports safe auto-correction (--auto-correct).
@@ -17,7 +17,7 @@
     CONTENTS
   end
 
-  let(:autocorrectable_rule_which_offence_count_is_2) do
+  let(:autocorrectable_rule_which_offense_count_is_2) do
     RubocopChallenger::Rubocop::Rule.new(<<~CONTENTS)
       # Offense count: 2
       # This cop supports safe auto-correction (--auto-correct).
@@ -27,7 +27,7 @@
     CONTENTS
   end
 
-  let(:autocorrectable_rule_which_offence_count_is_13) do
+  let(:autocorrectable_rule_which_offense_count_is_13) do
     RubocopChallenger::Rubocop::Rule.new(<<~CONTENTS)
       # Offense count: 13
       # This cop supports safe auto-correction (--auto-correct).
@@ -51,7 +51,7 @@
     CONTENTS
   end
 
-  let(:unautocorrectable_rule_which_offence_count_is_4) do
+  let(:unautocorrectable_rule_which_offense_count_is_4) do
     RubocopChallenger::Rubocop::Rule.new(<<~CONTENTS)
       # Offense count: 4
       Style/Documentation:
@@ -74,10 +74,10 @@
   describe '#all_rules' do
     let(:rules_which_are_ordered_by_offense_count) do
       [
-        autocorrectable_rule_which_offence_count_is_1,
-        autocorrectable_rule_which_offence_count_is_2,
-        unautocorrectable_rule_which_offence_count_is_4,
-        autocorrectable_rule_which_offence_count_is_13
+        autocorrectable_rule_which_offense_count_is_1,
+        autocorrectable_rule_which_offense_count_is_2,
+        unautocorrectable_rule_which_offense_count_is_4,
+        autocorrectable_rule_which_offense_count_is_13
       ]
     end
 
@@ -107,8 +107,8 @@
 
       it 'rejects to be ignored rules' do
         expect(todo_reader.all_rules).to eq [
-          autocorrectable_rule_which_offence_count_is_2,
-          unautocorrectable_rule_which_offence_count_is_4
+          autocorrectable_rule_which_offense_count_is_2,
+          unautocorrectable_rule_which_offense_count_is_4
         ]
       end
     end
@@ -117,9 +117,9 @@
   describe '#auto_correctable_rules' do
     let(:rules_which_are_ordered_by_offense_count) do
       [
-        autocorrectable_rule_which_offence_count_is_1,
-        autocorrectable_rule_which_offence_count_is_2,
-        autocorrectable_rule_which_offence_count_is_13
+        autocorrectable_rule_which_offense_count_is_1,
+        autocorrectable_rule_which_offense_count_is_2,
+        autocorrectable_rule_which_offense_count_is_13
       ]
     end
 
@@ -132,7 +132,7 @@
   describe '#least_occurrence_rule' do
     it 'returns a auto correctable rule with the least count of occurrences' do
       expect(todo_reader.least_occurrence_rule).to eq(
-        autocorrectable_rule_which_offence_count_is_1
+        autocorrectable_rule_which_offense_count_is_1
       )
     end
   end
@@ -140,7 +140,7 @@
   describe '#most_occurrence_rule' do
     it 'returns a auto correctable rule with the most count of occurrences' do
       expect(todo_reader.most_occurrence_rule).to eq(
-        autocorrectable_rule_which_offence_count_is_13
+        autocorrectable_rule_which_offense_count_is_13
       )
     end
   end
@@ -148,9 +148,9 @@
   describe '#any_rule' do
     it 'returns a auto correctable rule at random' do
       expect(todo_reader.any_rule)
-        .to eq(autocorrectable_rule_which_offence_count_is_1)
-        .or eq(autocorrectable_rule_which_offence_count_is_2)
-        .or eq(autocorrectable_rule_which_offence_count_is_13)
+        .to eq(autocorrectable_rule_which_offense_count_is_1)
+        .or eq(autocorrectable_rule_which_offense_count_is_2)
+        .or eq(autocorrectable_rule_which_offense_count_is_13)
     end
   end
 end