An OCT apparatus includes an OCT optical system, a processor that processes a signal from the OCT optical system, and a light guiding optical system disposed on a measurement light path of the OCT optical system. The light guiding optical system forms a pivot point, at which a measurement light turns based on motion of an optical scanner deflecting the measurement light, in an anterior portion of a subject eye, and guides the measurement light passed through the pivot point to a fundus. The OCT optical system includes a compensation unit that compensates for an amount of change in a light path length of the measurement light path between a state in which an angle-of-view switching optical system is inserted and a state in which the angle-of-view switching optical system is retracted.