Disclosed herein is a device that includes: a substrate having a gate trench; a gate electrode embedded in the gate trench with an intervention of a gate insulation film; and an embedded insulation film embedded in the gate trench. The substrate includes a first impurity diffusion region in contact with the embedded insulation film and a second impurity diffusion region in contact with the gate insulation film. The gate trench including a first trench portion extending in a first direction and second and third trench portions branching from the first trench portion and extending in a second direction that crosses the first direction. The gate electrode including first, second and third electrode portions embedded in the first, second and third trench portions of the gate trench, respectively. The first impurity diffusion region being sandwiched between the second and third electrode portions.