In a bidirectional surge protection device formed on a semiconductor substrate, buried layers, which have the same conduction type as and are higher in impurity concentration than the semiconductor substrate, are formed on the entire surfaces of the device regions provided on both surfaces of the semiconductor substrate or formed under emitter-push restraining layers alone, wherein injection of minority carriers from a surface opposite to the surface on which the device operates is restrained to lower a holding current. As a result, the bidirectional surge protection device easily becomes OFF once it becomes ON.