To provide a focal point adjustment device capable of properly performing focal point adjustment of a photographic optical system.

A focal point adjustment device includes: a first focal point adjustment optical system (212) that adjusts a focal point state of a photographic optical system by moving in an optical axis direction; a second focal point adjustment optical system (140) that contains an optical medium, includes a transparent parallel flat plate deformable in a width direction, and adjusts the focal point state of the photographic optical system as the thickness of the transparent parallel flat plate changes; and control means (170) that controls the first focal point adjustment optical system and the second focal point adjustment optical system.