A semiconductor device may be provided with a semiconductor substrate, an upper electrode, a lower electrode and a gate electrode provided within a trench via a gate insulator film. The semiconductor substrate may include a p-type body layer being in contact with the upper electrode, an n-type drift layer intervening between the body layer and the lower electrode, a p-type floating region provided along a bottom surface of the trench, and a p-type connection region extending between the body layer and the floating region along a side surface of the trench. The trench may include a first section where the connection region is not provided and a second section where the connection region is provided. An inclination angle of the side surface of the trench in the second section may be greater than an inclination angle of the side surface of the trench in the first section.