The present invention provides a semiconductor device realizing reduced occurrence of a defect such as a crack at the time of adhering elements to each other. The semiconductor device includes a first element and a second element adhered to each other. At least one of the first and second elements has a pressure relaxation layer on the side facing the other of the first and second elements, and the pressure relaxation layer includes a semiconductor part having a projection/recess part including a projection projected toward the other element, and a resin part filled in a recess in the projection/recess part.