This optical scanning endoscope apparatus can correct the white balance even when bending occurs in the illumination fiber. An optical scanning endoscope apparatus includes an illumination fiber that guides illumination light composed of RGB wavelengths (colors), an actuator that drives the tip of the illumination fiber and repeatedly scans the illumination light over an object, a photodetector that detects light obtained from the object by scanning of the illumination light, a signal processor that generates an image based on output of the photodetector, and a light amount detector for white balance that detects the light amount of light of RGB wavelengths from a portion of the illumination light guided by the illumination fiber. Based on the light amount of light of each of the RGB wavelengths detected by the light amount detector for white balance, the controller adjusts the white balance of the generated image.