Estimating determines, on the basis of processed quantized values, a quantization interval for quantizing input element values, which are elements of input values serving as a processing object and determines, on the basis of the processed quantized values, a probability distribution of quantization value candidates, which are candidates of quantized values of the input element values; quantizing uses the quantization interval to quantize the input element values and determine a quantized value; and entropy encoding uses the probability distribution to perform entropy encoding of a quantization time sequence which includes quantized value codes indicating the quantized values of the input element values.