A sheet processing apparatus of an embodiment includes a spring member which supports a support leg provided on an end bottom of a finishing apparatus at a side of an image forming apparatus and is extendable in a height direction, a sheet feed port which is formed in the finishing apparatus to be opposite to a sheet discharge port of the image forming apparatus and has a width wider than a width of the sheet discharge port in the height direction, sheet discharge guides which are arranged to be opposite to each other at an exit of the sheet discharge port and sandwich a conveyance path of the sheet in the image forming apparatus, sheet feed guides which are arranged to be opposite to each other at an inlet of the sheet feed port and sandwich a conveyance path of the sheet in the finishing apparatus, electromagnets provided at ends of the sheet feed guides at a side of the sheet feed port, and magnetic members which are rotatably provided to ends of the sheet discharge guides at a side of the sheet discharge port and are attracted by the electromagnets.