Provided is a method for manufacturing a thermally-assisted magnetic recording head with “composite slider structure”. In the method, the waveguide is irradiated with a first light from opposed-to-medium surface side, and the passing first light is detected on back surface side to obtain an image of the light-receiving end surface, and a light-receiving center position is determined from the image. Further, the light source is irradiated with a second light from opposite side to joining surface, and the passing second light is detected on the joining surface side to obtain an image of the light-emitting end surface, and a light-emitting center position is determined from the image. Then, the slider and the light source unit are moved based on the determined positions of the light-receiving and light-emitting centers, aligned and bonded. As a result, alignment can be performed with high accuracy in a short process time under simplified process.