diff --git a/plotter/main.py b/plotter/main.py
index 5680c7ee3dd9792f891dd150f0aa5e003d103b67..2deb324dfa7eed28d1d28acd4c260dd9dd6ddffb 100755
--- a/plotter/main.py
+++ b/plotter/main.py
@@ -60,7 +60,7 @@ def avg_plot(filename, out = './', oname = 'fig.png', var=[None], mval=[None]):
     Plot.set(args, if_manual_plot=manual_plot, if_save_result=save_result)
     Plot.avg_plot()
 
-def plot_diff(filename, out = './', oname = 'fig.png', var=[None], mval=[None], ndim = 1):
+def plot_diff(filename, ndim, out = './', oname = 'fig.png', var=[None], mval=[None]):
     Plot = Plotter()
     args = Args(filename, Plot.plot_diff, var=var, mval=mval, oname=oname, out=out, ndim=ndim)
     Plot.set(args, if_manual_plot=manual_plot, if_save_result=save_result)