A low-profile biometrics authentication system capable of achieving high security level authentication is provided. A biometrics authentication system 1 includes a light source 10, a light guide section 11A, a diffraction section 11B, a microlens array 12, an image pickup device 13, an image processing section 14, a pattern storing section 15, an authentication section 16, a voltage supply section 17, a light source driving section 181, an image pickup device driving section 182 and a control section 19. When light L0 emitted from the light source 10 propagates through the light guide section 11A by total reflection, and then enters the diffraction section 11B, light L1 diffracted at a different angle from an incident angle is generated. Thereby, the light guide section 11A functions as a surface-emitting light source, and total reflection conditions in the light guide section 11A are not satisfied, and the light L1 is guided to the outside of the light guide section 11A, thereby light is sufficiently applied to the inside of the living body 2.