diff --git a/app/views/fluentd/settings/in_tail/after_file_choose.html.haml b/app/views/fluentd/settings/in_tail/after_file_choose.html.haml
index 1311151..8c494c9 100644
--- a/app/views/fluentd/settings/in_tail/after_file_choose.html.haml
+++ b/app/views/fluentd/settings/in_tail/after_file_choose.html.haml
@@ -12,7 +12,7 @@
     = f.text_field :path, class: "form-control", disabled: true
   = render partial: "shared/vue/in_tail_format", locals: { file: f.object.path, formats: @setting.known_formats, initialSelected: f.object.format || @setting.guess_format }
 
-  %pre= file_tail(@setting.path, Settings.in_tail_preview_target_line).join("\n")
+  %pre= file_tail(@setting.path, Settings.in_tail_preview_line_count).join("\n")
 
   %p
     = f.submit t('terms.next'), class: "btn btn-lg btn-primary pull-right"
diff --git a/config/application.yml b/config/application.yml
index db5addf..c2df865 100644
--- a/config/application.yml
+++ b/config/application.yml
@@ -3,7 +3,7 @@ defaults: &defaults
   default_log_tail_count: 30
   histories_count_in_preview: 5
   max_backup_files_count: 100
-  in_tail_preview_target_line: 40
+  in_tail_preview_line_count: 40
   recommended_plugins:
     - category: filter
       name: "rewrite-tag-filter"
diff --git a/lib/regexp_preview.rb b/lib/regexp_preview.rb
index d754af0..6271a5a 100644
--- a/lib/regexp_preview.rb
+++ b/lib/regexp_preview.rb
@@ -36,7 +36,7 @@ class RegexpPreview
 
   def matches_single_line
     reader = FileReverseReader.new(File.open(file))
-    matches = reader.tail(Settings.in_tail_preview_target_line).map do |line|
+    matches = reader.tail(Settings.in_tail_preview_line_count).map do |line|
       result = {
         :whole => line,
         :matches => [],
@@ -60,7 +60,7 @@ class RegexpPreview
     return [] if multiline_regexps.empty?
     reader = FileReverseReader.new(File.open(file))
     result = []
-    target_lines = reader.tail(Settings.in_tail_preview_target_line).map{|line| line << "\n" }
+    target_lines = reader.tail(Settings.in_tail_preview_line_count).map{|line| line << "\n" }
     target_lines.each_with_index do |line, line_no|
       if line.match(params[:format_firstline])
         lines = target_lines[line_no, multiline_regexps.length]