An insulated circuit board includes an insulated substrate, a first electrode, and a second electrode. A thin portion is formed in a corner portion, the corner portion being a region occupying, with regard to directions along outer edges from a vertex of at least one of the first and second electrodes in plan view, a portion of a length of the outer edges, and the thin portion has a thickness smaller than that of a region other than the thin portion. The thin portion in at least one of the first and second electrodes has a planar shape surrounded by first and second sides orthogonal to each other as portions of the outer edges from the vertex, and a curved portion away from the vertex of the first and second sides.