An optical microcantilever capable of reducing loss when propagating light. An optical microcantilever 10 comprises a support 1, an optical waveguide 2, a light-blocking film 3, a reflecting film 4, a pointed tip 5, a microscopic aperture 6 formed at the end of the tip 5, and a mirror 7 for reflecting propagating light H propagated from a light input/output end 8 of the optical waveguide 2 towards the microscopic aperture 6.