Overload prevention is important for a force sensor in order to avoid fatal damage due to unexpected external forces. Until now, some mechanisms have been proposed which prevent damage of the sensor structure using screw and straight pin. However, nothing has been no reported regarding the utility of this mechanism. We proposed a unidirectional force sensor based on the H-slit type parallel beam structure in our previous work. This sensor structure alone can be realized for overload protection without any other parts and can be embedded as overload protection mechanism in the structure. In this paper, we verify the utility of conventional mechanisms and evaluate the usefulness of the slit type one which we have developed.