A signal processing device and a signal processing method are provided which can reproduce a smooth signal in the reproduction of a discrete signal having a non-uniform sample point interval. The device includes a coefficient calculation unit 4 that inputs a sample point signal E2 representative of the time of a sample point of a discrete signal E1 having a non-uniform sample point interval to obtain a coefficient of a sampling function corresponding to the discrete signal, and a reproduction signal calculation unit 5 that obtains a continuous reproduction signal E3 by calculating and outputting a function value within the sample point interval from the discrete signal and the value of the coefficient outputted by the coefficient calculation unit.