Provided is a surface emitting laser that is to be excited by an external light source and in which a light-emitting position is defined.A surface emitting laser includes a pair of reflecting mirrors (11, 15) and an active layer (13) that is arranged between the pair of reflecting mirrors (11, 15) and that is to be excited by light that is radiated from an external light source. A gap is formed between the active layer and one of the pair of reflecting mirrors (15), the oscillation wavelength of the surface emitting laser is changed, and a defining structure (20) that defines a light-emitting region of the active layer (13) is arranged in at least one of a region between the pair of reflecting mirrors (11, 15) and a region in at least one of the pair of reflecting mirrors (11, 15).