Patent ID: 7940488

Claim:
A gain adjusting device that outputs a gain value to an amplifier that amplifies, according to a first gain value, a first input signal acquired by reproducing first information from a plurality of first areas having the first information recorded therein area by area in order, the amplifier amplifying, according to a second gain value, a second input signal acquired by reproducing second information pursuant to reproduction of the first information, from a second area that is adjacent to the first area and that has the second information recorded at a recording level different from that of the first information, the gain adjusting device comprising: a first gain value output unit that when the first input signal is amplified, outputs the first gain value following a change in the first input signal, to the amplifier so that a level of the amplified signal becomes constant; and a second gain value output unit that when the second input signal is amplified, outputs the second gain value following a change in the first gain value output from the first gain value output unit, to the amplifier so that a level of the amplified signal becomes constant, wherein the second gain value output unit divides a first initial gain value preset as an initial value of the first gain value by a first gain value actually calculated by a first gain value calculating unit to determine a correction value, and multiplies the correction value by a second initial gain value preset as an initial value of the second gain value to calculate the second gain value to output the calculated second gain value to the amplifier.