Frequency characteristic setting circuitry for an amplifier generates frequency band data groups using a plurality of characteristic pattern data groups stored in a memory. Each of the frequency band data groups is made by making each item of data of a characteristic pattern data group retrieved from among a plurality of characteristic pattern data groups stored in the memory correspond to each frequency in a designated frequency band. The data groups generated for a plurality of frequency bands are combined together and the equalizing characteristic of the amplifier is controlled according to a characteristic pattern data group obtained by the combination.