--- a/src/c-parser.c
+++ b/src/c-parser.c
@@ -1668,6 +1668,7 @@
 {
     static ScmObj trigger_line = SCM_FALSE;
     ScmObj line_str;
+    ScmObj rx;
 
     /* skip the first line '# 1 "<stdin>"' */
     Scm_ReadLineUnsafe(SCM_PORT(in));
@@ -1682,7 +1683,22 @@
         }
     }
 
-    while (!SCM_EOFP(line_str = Scm_ReadLineUnsafe(SCM_PORT(in)))) {
+    rx = Scm_RegComp(SCM_STRING(SCM_MAKE_STR_IMMUTABLE("^#\\s+\\d+\\s+\"<stdin>\"")), 0);
+    line_str = Scm_ReadLineUnsafe(SCM_PORT(in));
+    while (!SCM_EOFP(line_str)) {
+        ScmObj body_str = line_str;
+        while (!SCM_EOFP(line_str = Scm_ReadLineUnsafe(SCM_PORT(in)))
+               && SCM_STRING_LENGTH(line_str) >= 13
+#ifdef SCM_REGEXP_MULTI_LINE
+               && SCM_REGMATCHP(Scm_RegExec(SCM_REGEXP(rx), SCM_STRING(line_str), SCM_UNDEFINED, SCM_UNDEFINED))) {
+#else
+               && SCM_REGMATCHP(Scm_RegExec(SCM_REGEXP(rx), SCM_STRING(line_str)))) {
+#endif
+            if (SCM_EOFP(line_str = Scm_ReadLineUnsafe(SCM_PORT(in)))) {
+                Scm_Error("[bug] unexpected EOF while parsing macro body");
+            }
+            body_str = Scm_StringAppend2(SCM_STRING(body_str), SCM_STRING(line_str));
+        }
         if (SCM_NULLP(macro_list)) {
             Scm_Error("[bug] lost macro body");
         } else {
@@ -1690,7 +1706,7 @@
             macro_list = SCM_CDR(macro_list);
             Scm_FilenameSet(SCM_CAAR(pos_name_args));
             Scm_LineNumberSet(SCM_INT_VALUE(SCM_CDAR(pos_name_args)));
-            parse_macro_body(SCM_CADR(pos_name_args), SCM_CDDR(pos_name_args), line_str);
+            parse_macro_body(SCM_CADR(pos_name_args), SCM_CDDR(pos_name_args), body_str);
         }
     }