A deformation detection sensor which combines a magnetic resin dispersing a magnetic filler in a resin with a magnetic sensor, of which stability of detection property is highly enhanced. The deformation detection sensor comprises a magnetic resin-containing polymer foam which comprises a magnetic resin, in which a magnetic filler is contained, and a polymer foam in which the magnetic resin is included, and a magnetic sensor that detects a magnetic change caused by a deformation of the magnetic resin-containing polymer foam, wherein the magnetic resin has an elastic modulus of 0.1 to 10 MPa, and a production thereof.