To reduce the effect of directly reflected light on a contact-surface side of a contact member, a biological information detector includes a light-emitting part, a light-receiving part, a reflecting part, a protecting part for protecting the light-emitting part, and a substrate. The protecting member is formed from a material that is transparent with respect to a wavelength of the light emitted by the light-emitting part and has a contact member provided with a contact surface in contact with the detection site. Light emitted from the light-emitting part is inhibited from reflecting once on a contact-surface side of the contact member of the protecting part and being incident on a light-receiving region of the light-receiving part.
