A light-receiving element includes a group III-V compound semiconductor stacked structure that includes an absorption layer having a pn-junction therein. The stacked structure is formed on a group III-V compound semiconductor substrate. The absorption layer has a multiquantum well structure composed of group III-V compound semiconductors, and the pn-junction is formed by selectively diffusing an impurity element into the absorption layer. A diffusion concentration distribution control layer composed of a III-V group semiconductor is disposed in contact with the absorption layer on a side of the absorption layer opposite the side adjacent to the group III-V compound semiconductor substrate. The bandgap energy of the diffusion concentration distribution control layer is smaller than that of the group III-V compound semiconductor substrate. The concentration of the impurity element selectively diffused in the diffusion concentration distribution control layer is 5×1016/cm3 or less toward the absorption layer.