An oxygen saturation measuring sensor is capable of increasing reliability of information of parts having different depth and includes a pad attachable to a human body； plural light sources arranged on the pad to be adjacent in a separate state, and irradiate near-infrared light； plural light receiving elements arranged on the pad to be adjacent in a separate state and correspond one to one to the plural light sources with reference to a common center with an innermost side of the plural light sources, and that receive transmitted light from the corresponding plural light sources； and a ROM unit that stores a reference value through measuring transmitted light using a phantom in advance and stores a light receiving amount of the transmitted light received by the plural light receiving elements.
