In a photoelectric conversion/connection device (100) including an optical element (320), a mounting board (310) on which the optical element is mounted, and an optical connector (400) which is connected to the mounting board so as to be optically connected to the optical element, the optical connector (400) is arranged on a surface (310a) opposite to a mounting surface (310b) of the mounting board (310) and the optical element (320) is exposed. The photoelectric conversion/connection device (100) includes a motherboard (210) having a main surface (210a) and an electric connector (220) to be mounted on the main surface of the motherboard. The electric connector (220) is detachably connected to the mounting board (310).