PURPOSE: To provide a semiconductor device, especially a semiconductor device wherein it is constituted by a triple diffusion operation, current concentration in the central part of an emitter region is relaxed and its electric characteristic such as its secondary breakdown-resistant amount or the like is improved.

CONSTITUTION: A base region 2 is formed on a semiconductor substrate, and an emitter region 3 is formed inside the base region 2. The outer edge 7 of the emitter region 3 inside the base region 2 is comb-shaped. A punched part 4A used to expose the base region 2 at the inside of the emitter region 3 is extended up to a part near the comb-shaped outer edge 7 of the emitter region 3. The outer shape of the punched part 4A may be a comb shape extended along the comb-shaped outer edge 7. Thereby, the junction face between the punched part 4A and the emitter region 3 is expanded, and it is relaxed that an electric current is concentrated.