Semiconductor device

First and second p-type anode layers (2,3) are provided side by side on a drift layer (1). N-type cathode layer (5) and p-type cathode layer (6) are provided side by side below the drift layer (1). An n-type buffer layer (7) is provided between the drift layer (1) and the n-type cathode layer (5) and between the drift layer (1) and the p-type cathode layer (6). The first p-type anode layer (2,2a,2b) has a greater diffusion depth than a diffusion depth of the second p-type anode layer (3). The first p-type anode layer (2,2a,2b) has a greater impurity concentration than an impurity concentration of the second p-type anode layer (3). The n-type cathode layer (5) has a greater diffusion depth than a diffusion depth of the p-type cathode layer (6). The n-type cathode layer (5) has a greater impurity concentration than an impurity concentration of the p-type cathode layer (6).