A semiconductor device includes a semiconductor substrate and a super junction structure on the substrate. The super junction structure is constructed with p-type and n-type column regions that are alternately arranged. A p-type channel layer is formed to a surface of the super junction structure. A trench gate structure is formed to the n-type column region. An n+-type source region is formed to a surface of the channel layer near the trench structure. A p+-type region is formed to the surface of the channel layer between adjacent n+-type source regions. A p-type body region is formed in the channel layer between adjacent trench gate structures and in contact with the p+-type region. Avalanche current is caused to flow from the body region to a source electrode via the p+-type region without passing through the n+-type source region.