To solve such a problem that the quantity of light reaching a phase difference detection system and an imaging device is reduced in the case of guiding a part of photographic luminous flux to the phase difference detection system with a half mirror and guiding the rest to the imaging device.

This camera having a mount part 3 to/from which a photographic lens 1 can be attached/detached is provided with a prism type optical device 4 arranged in the vicinity of the mount part and having a separating action surface 41 to separate a luminous flux component (or a luminous flux component in an infrared region) equal to or above a wavelength region near the infrared region out of luminous flux including the luminous flux component in a visible wavelength region made incident on a photographing optical path and going toward an imaging surface, and a detection optical system 50 to which the luminous flux component separated by the separating action surface is guided.