To enable high-precision measurement by a weight sensor, which utilizes an ultra-magnetostrictor for detecting a load quantity or the like in a washing machine.

A second coil 6 for causing an impulse current to flow to remove hysteresis, is formed differently from a first coil 3 for causing an oscillating current of LC oscillation to flow, to detect the change of the inductance of the ultra-super magnetostrictor 2 caused by the change of an external load, and is doubly wound around the ultra-magnetostrictor 2. Consequently, hysteresis can be surely removed, since it is possible for the second coil 6 to have a large wire diameter, which corresponds to the impulse current. Also, since the ultra-magnetostrictor 2 is hardly influenced by heat generation of the second coil 2, even if the second coil 2 generates heat by a flow of an impulse current, its inductance change caused by a temperature change becomes smaller, and the detection precision is increased.