To obtain an optoelectronic device which can be monitored accurately by employing a transparent resin surface for reflecting a rear emission light toward the surface of a light receiving element.

A laser diode chip 7 emits a laser light 10 from front and rear emission surfaces 15, 16 (front emission light 17, rear emission light 18). The rear emission light 18 arrives directly, or along with a light reflected on the surface of a light receiving element 21), at the inclining surface 25 of a package 2 made of synthetic resin. More specifically, the rear surface 24 perpendicularly intersecting the extension of the resonance surface 11 of laser diode 7 is inclining 25 in the way thereof. The rear emission light 18 is reflected on the surface 25 inclining to return the majority of reflected light 26 back to the surface (e.g. light receiving surface) of light receiving element 21. This structure increases the monitor current to facilitate the monitoring.