diff --git a/hwpfilter/source/formula.h b/hwpfilter/source/formula.h
index d0d4f9805c4e..ebdb1acc3b84 100644
--- a/hwpfilter/source/formula.h
+++ b/hwpfilter/source/formula.h
@@ -53,7 +53,7 @@ public:
     void setAttributeListImpl( AttributeListImpl *p )
     {
         pList = p;
-        rList = (XAttributeList *) pList;
+        rList = static_cast<XAttributeList *>(pList);
     }
     int parse();
 private:
diff --git a/hwpfilter/source/hgzip.cxx b/hwpfilter/source/hgzip.cxx
index baf3b20e43f5..915ea3135af7 100644
--- a/hwpfilter/source/hgzip.cxx
+++ b/hwpfilter/source/hgzip.cxx
@@ -61,9 +61,9 @@ gz_stream *gz_open(HStream & _stream)
     s = static_cast<gz_stream *>(ALLOC(sizeof(gz_stream)));
     if (!s)
         return Z_NULL;
-    s->stream.zalloc = (alloc_func) 0;
-    s->stream.zfree = (free_func) 0;
-    s->stream.opaque = (voidpf) 0;
+    s->stream.zalloc = nullptr;
+    s->stream.zfree = nullptr;
+    s->stream.opaque = nullptr;
     s->stream.next_in = s->inbuf = Z_NULL;
     s->stream.next_out = s->outbuf = Z_NULL;
     s->stream.avail_in = s->stream.avail_out = 0;
diff --git a/hwpfilter/source/hwpreader.cxx b/hwpfilter/source/hwpreader.cxx
index bcdf9d154640..a68a29b294b4 100644
--- a/hwpfilter/source/hwpreader.cxx
+++ b/hwpfilter/source/hwpreader.cxx
@@ -112,7 +112,7 @@ struct HwpReaderPrivate
 HwpReader::HwpReader()
 {
     pList = new AttributeListImpl;
-    rList = (XAttributeList *) pList;
+    rList = static_cast<XAttributeList *>(pList);
     d = new HwpReaderPrivate;
 }
 
diff --git a/hwpfilter/source/hwpreader.hxx b/hwpfilter/source/hwpreader.hxx
index bb4e0d283101..15baadd89f09 100644
--- a/hwpfilter/source/hwpreader.hxx
+++ b/hwpfilter/source/hwpreader.hxx
@@ -189,7 +189,7 @@ Reference< XInterface > HwpImportFilter_CreateInstance(
 {
     HwpImportFilter *p = new HwpImportFilter( rSMgr );
 
-    return Reference< XInterface > ( (OWeakObject* )p );
+    return Reference< XInterface > ( static_cast<OWeakObject*>(p) );
 }
 
 Sequence< OUString > HwpImportFilter::getSupportedServiceNames_Static() throw ()
diff --git a/hwpfilter/source/lexer.cxx b/hwpfilter/source/lexer.cxx
index 9c7cea8820b7..341bebb31aa2 100644
--- a/hwpfilter/source/lexer.cxx
+++ b/hwpfilter/source/lexer.cxx
@@ -203,7 +203,7 @@ static int yy_n_chars;      /* number of characters read into yy_ch_buf */
 int yyleng;
 
 /* Points to current character in buffer. */
-static char *yy_c_buf_p = (char *) 0;
+static char *yy_c_buf_p = nullptr;
 static int yy_init = 1;     /* whether we need to initialize */
 static int yy_start = 0;    /* start state number */
 
@@ -230,7 +230,7 @@ static void *yy_flex_realloc YY_PROTO(( void *, yy_size_t ));
 static void yy_flex_free YY_PROTO(( void * ));
 
 typedef unsigned char YY_CHAR;
-FILE *yyin = (FILE *) 0, *yyout = (FILE *) 0;
+FILE *yyin = nullptr, *yyout = nullptr;
 typedef int yy_state_type;
 extern char *yytext;
 #define yytext_ptr yytext
@@ -1590,7 +1590,7 @@ static int yy_get_next_buffer()
 
                 b->yy_ch_buf = static_cast<char *>(
                     /* Include room in for 2 EOB chars. */
-                    yy_flex_realloc( (void *) b->yy_ch_buf,
+                    yy_flex_realloc( static_cast<void *>(b->yy_ch_buf),
                              b->yy_buf_size + 2 ));
                 }
             else
@@ -1811,12 +1811,12 @@ YY_BUFFER_STATE b;
         return;
 
     if ( b == yy_current_buffer )
-        yy_current_buffer = (YY_BUFFER_STATE) 0;
+        yy_current_buffer = nullptr;
 
     if ( b->yy_is_our_buffer )
-        yy_flex_free( (void *) b->yy_ch_buf );
+        yy_flex_free( static_cast<void *>(b->yy_ch_buf) );
 
-    yy_flex_free( (void *) b );
+    yy_flex_free( static_cast<void *>(b) );
     }