An infrared solid state imaging device includes: a first PN junction diode has a first shortest length that is a shortest length from a first junction surface to a second junction surface; a PN junction diode has a second shortest length that is a shortest length from the second junction surface to a third junction surface, the second shortest length being different from the first shortest length; an insulating film serving as an element isolation region which establishes electrical isolation between a first region of the first PN junction diode and a fourth region of the second PN junction diode, and so on; and a metal wire provided on a second region of the first PN junction diode and a third region of the second PN junction diode, wherein the first PN junction diode and the second PN junction diode are connected in series.