A two-dimensional photonic-crystal surface-emitting laser includes an active layer; and a photonic-crystal layer including a two-dimensional photonic-crystal light-amplification portion that is a first two-dimensional photonic-crystal region provided in a plate-shaped base body disposed on one side of the active layer, and includes an amplification-portion photonic band gap which is a photonic band gap formed between two photonic bands having a band edge at a predetermined point in a reciprocal lattice space, and a two-dimensional photonic-crystal light-reflection portion that is a second two-dimensional photonic-crystal region provided around the two-dimensional photonic-crystal light-amplification portion, and includes a reflection-portion photonic band gap which is a photonic band gap formed between two photonic bands having a band edge at the predetermined point of the reciprocal lattice space, wherein energy ranges of the amplification-portion photonic band gap and the reflection-portion photonic band gap partially overlap and are different.