A magnetic field detection sensor includes a first magneto-impedance element and a second magneto-impedance element each having a magnetic material, a bias coil applying a bias magnetic field to the magnetic body of the first magneto-impedance element, a high-frequency oscillation circuit supplying high-frequency current to the magnetic bodies of the first magneto-impedance element and the second magneto-impedance element, an AC bias circuit supplying AC bias current to the bias coil, a first detection circuit generating a first detection signal based on an impedance change of the first magneto-impedance element in a state of being applied with the bias magnetic field and an external magnetic field, and a second detection circuit which generates a second detection signal based on an impedance change of the second magneto-impedance element in a state of being applied with the external magnetic field and without the bias magnetic field.