--- a/bsfilter/bsfilter
+++ b/bsfilter/bsfilter
@@ -1057,9 +1057,6 @@
         else
           @m = MeCab::Tagger.new([$0, "-Ochasen"])
         end
-      when "chasen"
-        Chasen.getopt("-F", '%H %m\n', "-j")
-        @method = Proc::new {|s| chasen(s)}
       when "kakasi"
         @method = Proc::new {|s| kakasi(s)}
       else
@@ -1123,31 +1120,6 @@
       return array
     end
     
-    def chasen(str)
-      str = str.gsub(/[\x00-\x7f]/, ' ')
-      if (str =~ /\A +\z/)
-        return []
-      end
-      array = Array::new
-      Chasen.sparse(str).split("\n").each do |hinshi_token|
-        if (hinshi_token =~ /(.*) (.*)/)
-          hinshi = $1
-          token = $2
-          if (hinshi == "\xcc\xbe\xbb\xec")
-            if ((token =~ Reg_kanji_katakana) || (token.length > 2))
-              array.push(token)
-            end
-          else
-            token.gsub!(Reg_not_kanji_katakana, '')
-            if ((token =~ Reg_kanji) || (token.length > 2))
-              array.push(token)
-            end
-          end
-        end
-      end
-      return array
-    end
-    
     def block(str)
       tokens = str.scan(Reg_kanji)
       tokens.concat(str.scan(Reg_katakana))
@@ -1960,7 +1932,7 @@
 		specify the name of database type
 		"sdbm" by default
 
-        --jtokenizer|-j bigram|block|mecab|chasen|kakasi
+        --jtokenizer|-j bigram|block|mecab|kakasi
 		specify algorithm of a tokenizer for Japanese language
 		"bigram" by default
 
@@ -3144,8 +3116,6 @@
     when "block"
     when "mecab"
       require 'MeCab'
-    when "chasen"
-      require 'chasen.o'
     when "kakasi"
       require 'kakasi'
     else
--- a/test/test.rb
+++ b/test/test.rb
@@ -217,14 +217,9 @@
     @bsfilter2.setup($default_options + ["--jtokenizer", "bigram"])
     @bsfilter2.use_dummyfh
 
-    @bsfilter3 = Bsfilter::new
-    @bsfilter3.setup($default_options + ["--jtokenizer", "chasen"])
-    @bsfilter3.use_dummyfh
-
     @bsfilter0.run(@files)
     @bsfilter1.run(@files)
     @bsfilter2.run(@files)
-    @bsfilter3.run(@files)
 
     assert_equal(1, @bsfilter0.count_message(/tokenizer ja body ī/),  "@bsfilter0 2letters")
     assert_equal(0, @bsfilter0.count_message(/tokenizer ja body /), "@bsfilter0 3letters")
@@ -234,9 +229,6 @@
 
     assert_equal(1, @bsfilter2.count_message(/tokenizer ja body ī/), "@bsfilter2 2letters")
     assert_equal(0, @bsfilter2.count_message(/tokenizer ja body /), "@bsfilter2 3letters")
-
-    assert_equal(1, @bsfilter3.count_message(/tokenizer ja body ī/), "@bsfilter3 2letters")
-    assert_equal(1, @bsfilter3.count_message(/tokenizer ja body /), "@bsfilter3 3letters")
   end
 
   def teardown
@@ -325,16 +317,6 @@
     end
     @bsfilter.use_dummyfh
     @bsfilter.run(@files)
-    assert_equal(1, @bsfilter.count_message(/tokenizer ja body ī/), "2 letters")
-    assert_equal(1, @bsfilter.count_message(/tokenizer ja body /), "3 letters")
-  end
-
-  def test_chasen
-    assert_nothing_raised('Warning: ignore this test if chasen is NOT installed') do
-      @bsfilter.setup($default_options + ["--jtokenizer", "chasen"])
-    end
-    @bsfilter.use_dummyfh
-    @bsfilter.run(@files)
     assert_equal(1, @bsfilter.count_message(/tokenizer ja body ī/), "2 letters")
     assert_equal(1, @bsfilter.count_message(/tokenizer ja body /), "3 letters")
   end
