Sheet finishing apparatus and control method

A sheet finishing apparatus, comprising:

• a finishing unit configured to perform finishing on a sheet conveyed from an image forming apparatus;
• a sensor group including device sensors that are operated by a power source voltage supplied from the image forming apparatus and are for respectively detecting states of a plurality of devices in the finishing unit, and sheet sensors that are for detecting the sheet in the finishing unit;
• and
• a control unit that is operated by the power source voltage, controls the plurality of devices in the finishing unit in response to detection results of the sensor group, and, while a first finishing is being executed in the finishing unit, operates the sheet sensor, and stops execution of a different finishing and operation of the device sensor for the different finishing.