An optical scanning apparatus includes an optical fiber that emits illumination light from a distal end thereof toward a subject, an actuator that oscillates the distal end of the optical fiber, and a controller that controls the actuator so as to two-dimensionally scan the illumination light on the subject and so as to satisfy Conditional Expression of P1≤0.5×D, where D is a spot diameter of the illumination light on the subject, and P1 is a scanning-line pitch of the illumination light on the subject.
