A semiconductor device including: a fuse element; and a fuse window that is formed above a region including the fuse element, that includes a pair of first sidewalls extending in a first direction running along a direction that current flows in the fuse element and a pair of second sidewalls extending in a second direction intersecting the first direction, and that is formed with a projection projecting out from a sidewall side toward the inside at an inner wall of at least one out of the first sidewalls or the second sidewalls, the projection having a sidewall side width that is narrower than a projecting side width.