PURPOSE: To highly efficiently adjust a cantilever by comparing measured values of the repulsive force of a free end before correction with measured values after a base end is deformed by a prescribed amount and adjusting the fitting angle of the base end based on a required adjusting amount calculated.

CONSTITUTION: A probe 2 is composed of an arm, the central part of which is supported on a base 6 at an appropriate lever ratio and one end of the probe 2 is connected to the free end of a load cell 3, with a clamping section which loosely clamps the mobile member of an electromagnetic relay 1 being formed on the other end. The cell 3 and probe 2 are connected to each other in a fixed relation and the displacement of the clamping section of the probe 2 can be found from the moving amount of the cell 3. Then, by comparing measured values of the repulsive force of the free end of the probe 2 before correction with measured values after the base end is deformed by, for example, an empirically found prescribed amount and adjusting the fitting angle of the base end based on a required adjusting amount calculated from the compared result, the flexible deformation of the free end is set so that the repulsive force of the free end resulting from the deformation can become a prescribed value.