A 
semiconductor device includes: a 
semiconductor substrate of a first 
conductivity type; a 
semiconductor layer of a first 
conductivity type formed on a first main surface of the semiconductor substrate, the semiconductor layer including a first region for a 
cell portion and a second region for a terminating portion, the second region being positioned in an outer periphery of the first region, the terminating portion maintaining 
breakdown voltage by extending a depletion layer to relieve an 
electric field; junction pairs of semiconductor 
layers periodically arranged so as to form a line from the first region to the second region in a first direction parallel to the first main surface in the semiconductor layer and having mutually opposite 
conductivity types of impurities, each of the junction pair being composed of a first 
impurity diffusion layer of a second conductivity type formed from a surface of the semiconductor layer toward the semiconductor substrate and a second 
impurity diffusion layer of a first conductivity type formed from the surface of the semiconductor layer toward the semiconductor substrate and adjacently to the first 
impurity diffusion layer; a base layer of a second conductivity type selectively formed on each 
surface layer of the junction pairs which are formed in the first region, so as to connect with the first 
impurity diffusion layer and the second 
impurity diffusion layer in the same manner; a source layer of a first conductivity type selectively formed on each 
surface layer of the base 
layers of the second conductive type; a control 
electrode formed above each surface of the base 
layers and above each surface of the source layers via an insulating film; a first main 
electrode formed so as to cover the control 
electrode and to contact the source layers and the base layers in the same manner; and a second main electrode formed on a second main surface opposite to the first main surface of the semiconductor substrate.