A pulse oximeter (1, 2) includes a first light emitter (11) configured to generate first light, a second light emitter (12) configured to generate second light with a different wavelength from that of the first light, and a light receiver (13) configured to receive each of first return light of the first light from a living body and second return light of the second light from the living body. The pulse oximeter is provided with: a contact pressure detecting device (14) configured to detect a signal associated with contact pressure between the pulse oximeter and the living body； and an outputting device (100) configured to output information regarding oxygen saturation, on the basis of respective signals outputted from the light receiver due to the first return light and the second return light, and the detected signal associated with the contact pressure.
