This optical scanning endoscope apparatus includes an actuator that scans light from a light source over an object with a predetermined scan cycle, a light amount detector that detects the light amount from the light source, and a controller that controls output of the light source based on the light amount detected by the light amount detector. During each scan cycle by the actuator, the controller controls the light source so as to output light according to a predetermined output change pattern, sequentially calculates an integral value of the light amount detected by the light amount detector over a predetermined time period, and controls the maximum of the change in output of the light source due to the output change pattern so that the integral value does not exceed a predetermined standard value.
