A picture encoding apparatus divides an input picture into a plurality of regions and produces quantized transform coefficients of one of the regions. A zero/non-zero coefficient information encoding unit included in the picture encoding apparatus encodes information representing the respective quantized transform coefficients of the one region as either a zero coefficient or a non-zero coefficient. A non-zero coefficient encoding unit included in the picture encoding apparatus encodes non-zero quantized transform coefficient included among the quantized transform coefficients of the one region. The non-zero coefficient encoding unit is configured to select, from a probability model composed of a plurality of estimated probabilities, an estimated probability used to encode an absolute value of a next non-zero quantized transform coefficient of the one region. The estimated probability is selected from the probability model based on a quantity of already encoded non-zero quantized transform coefficients of the one region.