A light emission section, including a light emitting element such as a semiconductor laser, emits a light beam in accordance with communication data. A light reception section, including a light receiving element such as a photodiode, receives the light beam emitted by the light emission section. The light emission section and the light reception section are positioned and an emission angle and an incidence angle of the light beam are determined such that the light beam emitted by the light emission section to the light reception section is prevented from being reflected by a surface of the optical reception section and/or a mounting substrate and being returned to the light emission section.