An optical fiber is provided between a photodiode and a semiconductor active portion of a wide gap semiconductor element forming portion such that emitted light at the time of light emission of the semiconductor active portion of the wide gap semiconductor element forming portion is incident from an incident surface of the optical fiber, and is received from an emitting surface to the photodiode through the optical fiber. Specifically, the incident surface of the optical fiber is arranged so as to be opposed to a side surface portion of the wide gap semiconductor element forming portion, so that the emitted light at the time of light emission of the wide gap semiconductor element is incident on the incident surface.