A magnetic field application device includes a magnetic field application unit provided with a magnetic working substance, a permanent magnet, a yoke and a coil. The magnetic field application unit applies a magnetic field to the magnetic working substance. The yoke forms at least two closed magnetic circuits, each being a closed circuit that magnetically connects both ends in a magnetization direction of the permanent magnet. The coil is capable of changing an intensity of the magnetic field applied to the magnetic working substance. The coil is provided in at least one of the closed magnetic circuits. The magnetic field application unit is disposed in at least one of the closed magnetic circuits. A magnetic flux of the permanent magnet is branched to flow through two or more of the closed magnetic circuits including the closed magnetic circuit provided with the magnetic field application unit when the coil is non-energized.