A thermally assisted magnetic recording head includes a magnetic recording element part for writing, a main waveguide for assistance for receiving light, and a dummy waveguide component part provided in parallel to the main waveguide. The dummy waveguide component part includes a pair of waveguides having the same shape and dimensions including a first waveguide and a second waveguide that receive light from a back end surface opposite to an air bearing surface and guides the light toward the air bearing surface, and light emitting ends of the first waveguide and the second waveguide facing towards the air bearing surface have no shielding material, and are in a free condition so that the light intensity from the light emitting ends can be measured.