Provided is a photo detecting element including a body with an optical sensor and an amplification unit for amplifying a signal output from the optical sensor. The photo detecting element includes a driving voltage port that applies a driving voltage to the amplification unit, a ground port that provides a ground for the amplification unit, and a plurality of output ports interposed between the driving voltage port and the ground port, and outputting a signal received from the amplification unit. The driving voltage port, ground port, and plurality of output ports are disposed on the same one side of the body.