The 2D-PC surface emitting laser includes: a PC layer; and a lattice point for forming resonant-state arranged in the photonic crystal layer, and configured so that a light wave in a band edge in photonic band structure in the PC layer is diffracted in a plane of the PC layer, and is diffracted in a surface vertical direction of the PC layer. The perturbation for diffracting the light wave in the surface vertical direction of the PC layer is applied to the lattice point for forming resonant-state. The term “perturbation” means that modulation is periodically applied to the lattice point for forming resonant-state. For example, the periodic modulation may be refractive index modulation, hole-diameter modulation, or hole-depth modulation.