Can't use command+space to change input source

I have been having an issue regarding keyboard short-cut to change input source between Japanese and English on a new iMac running on Sierra. On my old Mac, I used "command+space" (Fig. 1) to change the input source, but now on Sierra I have to use "control+space" (Fig. 2), which is quite inconvenient. Could someone help me how to set my system so that I can use "command+space" to change the input source?