An infrared sensor manufacturing method according to this invention includes a step of forming a bridge structure of an insulating material on an Si substrate, a step of forming a vanadium oxide thin film on the bridge structure by a dry film forming method, a step of irradiating laser light onto the vanadium oxide thin film to thereby change material properties thereof, a step of forming the vanadium oxide thin film with the changed material properties into a bolometer resistor having a predetermined pattern, and a step of forming a protective layer of an insulating material so as to cover the bolometer resistor having the predetermined pattern and the bridge structure.