A light receiving element includes an InP substrate that is transparent to light having a wavelength of 3 to 12 μm, a buffer layer located in contact with the InP substrate, and a light-receiving layer having a multiple quantum well structure, the light-receiving layer having a cutoff wavelength of 3 μm or more and being lattice-matched with the buffer layer. In the light receiving element, the buffer layer is epitaxially grown on the InP substrate while the buffer layer and the InP substrate exceed a range of a normal lattice-matching condition, and the buffer layer is constituted by a GaSb layer.