PROBLEM TO BE SOLVED: To achieve respiration measurement in a natural state of a measurement object person by doing away with tightening applied to the measurement object person in time of the respiration measurement.SOLUTION: A respiration sensor 10 includes: a pair of electrodes 11 pinching the trunk of a measurement object person P and a detection device 12 obtaining the change of the electrostatic capacity between the pair of electrodes 11, and detecting the respiration of the measurement object person P from the change of the electrostatic capacity. Because detecting the respiration of the measurement object person P from the change of the electrostatic capacity, the respiration sensor 10 can perform respiration measurement in a natural state of the measurement object person P without applying a fastening force to the measurement object person P in the respiration measurement.