To reduce an operation sound to be emitted from an HDD, a heat dissipation fan, etc. by simple structure.

An operation sound reduction system is constituted so that an operation sound reduction signal in which the phase and amplitude are set so as to reduce the operation sound to be generated from an operation sound generation part 20 by being outputted from a speaker section 16 is preliminarily stored in a memory unit 21, is read at a prescribed timing and is outputted from the speaker section 16 by being multiplexed to the voice of a broadcast program. Furthermore, the operation sound is surely reduced by adjusting the phase and the amplitude of the operation sound reduction signal read from the memory unit 21 so that the operation sound to be generated from the operation sound generation section 20 becomes hardest to be heard or a level of the operation sound is minimized.