The disclosed optical scanning endoscope apparatus includes a scanner that scans an object with illumination light from a light source, a light amount detector that detects a light amount of the illumination light 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. The controller controls the output of the light source based on an integral value of the light amount detected by the light amount detector during an immediately prior predetermined period.
