What is provided is a subtractor, as a re-quantization device, which is configured to detect re-quantization noise, a discrete time filter which is configured to perform frequency weighting on the detected re-quantization noise, an adder which is configured to add an additional signal to quantization noise, and an additional signal selector which is configured to select a value at the present time of a column of an additional signal for minimizing the magnitude of quantization noise having been subjected to frequency weighting evaluated one sampling or more later.