A bidirectional Zener diode of the present invention includes a semiconductor substrate of a first conductivity type, a first electrode and a second electrode which are defined on the semiconductor substrate, and a plurality of diffusion regions of a second conductivity type, which are defined at intervals from one another on a surface portion of the semiconductor substrate, to define p-n junctions with the semiconductor substrate, and the plurality of diffusion regions include diode regions which are electrically connected to the first electrode and the second electrode, and pseudo-diode regions which are electrically isolated from the first electrode and the second electrode.