The component measuring device is provided with: a photometric block (72) having a mounting portion (87) having an opening so as to be opposed to a test paper (70), and having a reflected light optical path (110) for guiding reflected light (Lr) to a light receiving element (102), the reflected light optical path (110) communicating with the mounting portion (87); and a reflected light lens (88b) for condensing the reflected light (Lr) onto the light receiving element (102). The reflected light lens (88b) is formed as an aspheric lens for reducing at least spherical aberration of the reflected light (Lr) on a basis of a position of disposition of the light receiving element (102).