PURPOSE: To provide an on-vehicle sound field corrector which can correct the sound field of the car room space to the optimum condition in correspondence to the number of the passengers in the car room or the change of the boarding position.

CONSTITUTION: In an on-vehicle sound field corrector equipped with an FIR filter arithmetic part 10 for correction to convert the amplitude and phase characteristics of an digital audio input signal, a filter coefficient storing part 2 to store plural kinds of the filter coefficients of the FIR filter arithmetic part 10 for correction, a selecting means 3 to select one kind of the filter coefficient in correspondence to the seating condition of the passengers in the car room out of the filter coefficients stored in the filter coefficient storing part 2, and a filter coefficient replacing means 1 to replace the filter coefficient selected by the selecting means 3 with the filter coefficient of an FIR digital filter are provided. By the FIR digital filter to replace the filter coefficients, the correction to form the optimum sound field under the seating condition is performed.