An image forming apparatus includes a rotating polygon mirror, a motor, a bearing portion, a measurement processing portion, and a determination processing portion. The rotating polygon mirror causes a light beam emitted from the light source to be scanned. The motor rotates the rotating polygon mirror. The bearing portion rotatably supports a rotation shaft of the motor via a lubricant. The measurement processing portion measures a transition time that is a time required for the motor to transition from a stationary state to a driving state in which the motor rotates at a predetermined speed. The determination processing portion determines whether or not a maintenance is required, based on the transition time measured by the measurement processing portion.