A detector of a magnetic field probe includes a first wiring pattern formed on a first surface of a multilayer substrate and having a predetermined inclination with respect to an axial line direction of the magnetic field probe, a second wiring pattern formed on a second surface and having the predetermined inclination with respect to the axial line direction, and a first penetrating via penetrating through the multilayer substrate in the thickness direction and connecting a front end portion of the first wiring pattern and a front end portion of the second wiring pattern. A rear end portion of the first wiring pattern is connected to a conductor pattern configuring a strip line and a rear end portion of the second wiring pattern is connected to ground patterns configuring the strip line.