A semiconductor device includes a laminated substrate formed by laminating a plurality of semiconductor substrates, a concave part formed in the laminated substrate, and a semiconductor element mounted in the concave part. A method of manufacturing a semiconductor device includes a first step of forming a laminated substrate by laminating a plurality of semiconductor substrates, a second step of forming a concave part by etching the laminated substrate, and a third step of mounting a semiconductor element in the concave part.