Optical deflector including rotatable mirror part having flat and grooved reflection surfaces, and optical scanning apparatus

Provided is an optical deflector that detects an arbitrary deflection angle of a mirror part while avoiding the increase in the length of an optical sensor for detection of the deflection angle. An optical deflector 3 comprises: a mirror part 30 that has a flat reflection surface 38 and a grooved reflection surface 39, each of the flat reflection surface 38 and the grooved reflection surface 39 reflecting an incident light; and an actuator 32a to 32d that reciprocally turns the mirror part 30 about a rotation axis 36. The grooved reflection surface 39 has a plurality of longitudinal grooves 41 that extends parallel to the rotation axis 36. Each longitudinal groove 41 has a facing inclination surface 42a, 42b that is parallel to the rotation axis 36 and that has at least an opening-side portion of a facing inclination surface of a V-groove.