A two-dimensional photonic crystal optical resonator and an optical reflector being high in light retrieving efficiency and obtained by the following steps. A two-dimensional photonic crystal is produced by periodically arranging, in a slab-like main body (11), regions (holes) (12) each having a refractive index different from that of the main body (11). A waveguide (13) is formed in the crystal by providing holes (12) non-linearly. Two holes (12) a distance L apart in the length-wise direction of the waveguide are enlarged to form two acceptor type point defects (14). A distance L properly selected in this configuration can suppress light reflection and transmission at point defects (14) to allow us to efficiently retrieve light resonating at point defects (14). A properly selected distance L can increase a light reflectance at point defects (14) to allow applications as an optical resonator for allowing light to resonate between two point defects (14) and as an optical reflector for allowing light to reflect at two point defects (14).