A photonic crystal surface emission laser includes an active layer, and a photonic crystal layer made of a plate-shaped slab provided with modified refractive index area having a refractive index different from that of the slab, the modified refractive index areas being arranged on each of the lattice points of a first rhombic-like lattice and a second rhombic-like lattice in which both diagonals are mutually parallel and only one diagonal is of a different length, wherein ax1, ax2, ay, and n satisfy the following inequality:  1 a x ⁢ ⁢ 1 - 1 a x ⁢ ⁢ 2  ( 1 a x ⁢ ⁢ 1 + 1 a x ⁢ ⁢ 2 ) 2 + ( 2 a y ) 2 ≤ 1 n .