PROBLEM TO BE SOLVED: To provide a biological information detector mounted on a vehicle to detect the pulse waves of an occupant, which can correctly detect the pulse waves of the occupant at low irradiation light quantity while making the occupant be free from the burden of attachment of the detector.SOLUTION: A vehicle seat includes: a light-emitting section 21 for emitting irradiation light containing a near-infrared ray of a predetermined wavelength toward a predetermined part of a person who sits on the vehicle seat and a light-receiving section 22 for receiving light reflected from at least a pulse portion in the skin on the predetermined part of the sitting person, the reflected light being originated from the irradiation light emitted from the light-emitting section 21, and outputting a signal corresponding the strength of the reflected light which has been received. A partitioning section 23 for preventing the light-receiving section 22 from receiving the reflected light from the body surface on the predetermined part of the sitting person, the reflected light being originated from the irradiation light emitted by the light-emitting section 21, is formed between the light-emitting section 21 and the light-receiving section 22 in the vehicle seat to detect the pulse waves of the sitting person from the output signal of the light-receiving section 22.
