diff --git a/plotter/main.py b/plotter/main.py
index 7c6eb6343eaaa888fda515923a0feb34f2802162..7c9e06914691b85152b1f6fa950d8fe850eca662 100755
--- a/plotter/main.py
+++ b/plotter/main.py
@@ -14,7 +14,7 @@ def dump(filename, var=[None], mval=[None]):
     Plot.set(args, if_manual_plot=manual_plot, if_save_result=save_result)
     Plot.dump()
 
-def plot(filename, out = './', oname = 'fig.png', var=[None], mval=[None], min_y = None, max_y = None):
+def plot(filename, out = './', oname = [None], var=[None], mval=[None], min_y = None, max_y = None):
     Plot = Plotter()
     args = Args([filename], Plot.plot, var=var, mval=mval, oname=oname, out=out)
     Plot.set(args, if_manual_plot=manual_plot, if_save_result=save_result)