To provide a lens device capable of making the external form of an attaching frame minimum while arranging a focus lens driving means and a lens position detection means near a guide shaft being reference for guiding a rear focus lens in an optical axis direction.

Through a holding frame 62 housed in a mount attaching frame 20, a focus lens 36, a pair of voice coil motors (VCM) 66, and a magnetic sensor 120 are disposed in the lens device of a rear focus system. The VCM 66 and the magnetic sensor 120 are disposed near a first guide shaft 39 as a reference. Especially, the pair of VCMs 66 are disposed at the positions which are made to be symmetric by putting the first guide shaft 39 in between, and at the positions which can be proximate to the first guide shaft 39 (positions adjacent to first bosses for screw 130A and 130B for fixing a guide frame that supports the rear end of the first guide shaft 39).