Abstract: Upon receipt of a direction indication control signal s11, a sounding-body driving circuit 12 generates a driving signal s16 for generating a flashing operation sound which is an artificial striking sound similar to a striking sound of a mechanical relay. The driving signal s16 is output to a speaker 16 via an amplifier 14, and the flashing operation sound is outputted from the speaker 16, thereby obtaining the flashing operation sound which does not sound unusual to the driver. The sounding-body driving circuit 12 enables a plurality of rectangular wave signals having the same amplitude and different frequencies to be synthesized in sequence of time by first and second synthetic signal generating circuits 20A and 20B to thus generate first and second synthetic signals s14 and s15 as artificial striking sounds.

Abstract: Upon receipt of a direction indication control signal s11, a sounding-body driving circuit 12 generates a driving signal s16 for generating a flashing operation sound which is an artificial striking sound similar to a striking sound of a mechanical relay and outputs the driving signal s16 to a speaker 16 via an amplifier 14, and the flashing operation sound is outputted from the speaker 16, thereby obtaining the flashing operation sound which does not sound unusual to the driver. The sounding-body driving circuit 12 has a construction such that a plurality of rectangular wave signals having the same amplitude and different frequencies are synthesized in sequence of time by first and second synthetic signal generating circuits 20A and 20B to thus generate first and second synthetic signals s14 and s15 as artificial striking sounds, and the signals s14 and s15 are alternately outputted as driving signals s16 from a synthetic signal output circuit 22 at intervals of a predetermined time.