To facilitate the alteration of the interference sites (treating sites) without changing the positions of conductors for the body surfaces of the patients.

A first pair of high-frequency electrical signals is represented by A1 and A2 (for example, high-frequency H+low frequency α), a second pair of high-frequency electrical signals by B1 and B2 (for example, frequency H) and a third pair of high-frequency electrical signals by C1 and C2 (for example, frequency H+2α). The high-frequency electrical signals A1-C2 are applied to six conductors J1-J6 dispersed over the body surface of the patient through a switch device K2. With the switches R1-R3 of the switch device K2 off individually, the application of the high-frequency electrical signals to the conductors J1-J6 is made into a state as shown in Fig. 3 and the interference site is set at T1. When the switch R1 alone is turned on, the types of the conductors and the high-frequency electrical signals to be applied are altered and the interference site is shifted to T2 and T3 (Fig. 4). Likewise, the interference site can be shifted to T4 and T5 (Fig. 5) or T 6 and T7 (Fig. 6) according to the combination of the ON and OFF switchings of the switches R1-R3.