Disclosed is a post-processing apparatus configured to be coupled to an image forming apparatus or another post-processing apparatus. The post-processing apparatus includes: a post-processing unit that performs post-processing to a sheet that is conveyed; and a standby path arranged on an upstream side or a downstream side of the post-processing unit and capable of holding the sheet. The post-processing unit performs the post-processing in a state in which the sheet is partly in the standby path.