The present invention aims to increase an encoding efficiency when the occurrence probability of LPS (less probable symbol) is low. An encoding apparatus has a interval size (A), a interval limit value (C), divides a set interval which is set on a number line, selects a sub-interval corresponding to an occurring symbol, updates the interval size (A) and the interval limit value (C) with a limited precision based on the selected sub-interval size, and encodes a coordinate within the interval. Based on the probability (the occurrence probability of symbol) output from a learning memory, the sub-interval size (LSZ, dLSZ) and the sub-interval limit value are obtained. A correction value calculator computes the correction value based on the dLSZ, reflects the computed correction value (dA, dC) to the renormalized subinterval size (rA) and the renormalized sub-interval limit value (rC), updates the interval size (A7) to the sub-interval size, updates the interval limit value (C8) to the sub-interval limit value, and outputs a code.