diff --git a/pypcd/pypcd.py b/pypcd/pypcd.py
index 93f58e8..db0fb52 100644
--- a/pypcd/pypcd.py
+++ b/pypcd/pypcd.py
@@ -77,6 +77,8 @@ def parse_header(lines):
     for ln in lines:
         if ln.startswith('#') or len(ln) < 2:
             continue
+        ln = ln.replace('_','s',1)
+        ln = ln.replace('_','m',1)
         match = re.match('(\w+)\s+([\w\s\.]+)', ln)
         if not match:
             warnings.warn("warning: can't understand line: %s" % ln)