An image forming apparatus includes: a sensor section, an oscillation mechanism, a control section, and an object determination section. The sensor section has a pyroelectric infrared sensor detecting presence of an object based on an infrared ray change. The oscillation mechanism turns the sensor section. The control section, upon the detection of the object by the sensor section, makes the oscillation mechanism start the turning operation. The object determination section, after the turning operation of the sensor section starts from a predefined initial position, determines that the object exists in a case where a state in which the object is detected by the sensor section continues for a predefined first period of time, and determines that the object does not exist in a case where the state in which the object is detected does not continue for the first period of time.