PURPOSE: To adjust the engine with the linear governor control characteristic accurately and responsively by relatively positioning a rotor and an oscillating member such that the rotation axis of the rotor and the oscillating shaft of the oscillating member are on the coaxial line.

CONSTITUTION: When a disc 2 is rotated to the direction A simultaneously with the rotation of an engine, eddy current is generated at the disc 2 by the magnetic field formed by a permanent magnet 5, and the electromagnetic force for oscillating an oscillating member 4 in the rotating direction of the disc 2 between the eddy current and the magnetic field of the permanent magnet 5 is generated. The extent of the generated electromagnetic force is approximately proportioned to the speed of the disc 2, that is, the engine speed, and the oscillating member is oscillated opposing to a governor spring 6 so as to adjust the engine. In this case, as the disc 2 and the oscillating member 4 are relatively positioned such that the rotation axis 1 of the disc 2 and the oscillating shaft 3 of the oscillating member 4 are on the coaxial line, the rotating direction of the disc 2 coincides with that of the oscillating member 4 so as to obtain the rotating force of the oscillating shaft 3 proportioned to the engine speed.