Abstract: An OCT device includes an OCT optical system, a controller which acquires OCT data based on a signal from the OCT optical system and controls the OCT optical system to execute an OCT data acquisition operation, a light guide optical system, and an adjuster adjusting a three-dimensional position of the light guide optical system with respect to a subject eye. The light guide optical system includes an optical scanner scanning the subject eye with the measurement light, and an objective optical system which is disposed between the optical scanner and the subject eye and forms a pivot point around which the measurement light passing through the optical scanner is pivoted. The controller guides the three-dimensional position such that the pivot point is arranged at a target position set between the subject eye and the objective optical system, and further executes the OCT data acquisition operation at the target position.