A chemical sensor that enables high detection accuracy that includes a soft-magnetic-material film, a magnetoresistance-effect element, a first film disposed over the soft-magnetic-material film, and a second film disposed over the magnetoresistance-effect element, wherein, when viewed from a direction perpendicular to the film surface of the soft-magnetic-material film, the soft-magnetic-material film is disposed at least partially so as not to overlap the magnetoresistance-effect element; when viewed from the direction perpendicular to the film surface of the soft-magnetic-material film, the magnetoresistance-effect element is disposed at least partially so as not to overlap the soft-magnetic-material film; and the second film has higher solubility in a specific liquid than the first film.