An encoding device, comprising: an order table generation unit configured to generate an order table showing arrangement order of mixing coefficients determined on the basis of distances between a plurality of input speakers and a plurality of output speakers, the mixing coefficients being mixing coefficients of the plurality of input speakers prepared for the plurality of respective output speakers and being used in a mixing process for converting audio signals of a plurality of channels corresponding to arrangement of the plurality of input speakers into audio signals of a plurality of channels corresponding to arrangement of the plurality of output speakers; a rearrangement unit configured to rearrange the plurality of mixing coefficients in the order shown in the order table; a difference calculation unit configured to calculate a differential value between two consecutive mixing coefficients among the mixing coefficients rearranged in the order; an encoding unit configured to encode the differential value calculated for each of the mixing coefficients; a symmetry table generation unit configured to generate a symmetry table showing symmetry of a positional relationship between the mixing coefficients; and a symmetry determination unit configured to determine, on the basis of the symmetry table, that, in the case where the mixing coefficient and an other mixing coefficient having the positional relationship symmetric to the mixing coefficient have the same value, the mixing coefficient and the other mixing coefficient are symmetric, wherein the encoding unit does not encode the differential value of the mixing coefficient determined to be symmetric to the other mixing coefficient. an order table generation unit configured to generate an order table showing arrangement order of mixing coefficients determined on the basis of distances between a plurality of input speakers and a plurality of output speakers, the mixing coefficients being mixing coefficients of the plurality of input speakers prepared for the plurality of respective output speakers and being used in a mixing process for converting audio signals of a plurality of channels corresponding to arrangement of the plurality of input speakers into audio signals of a plurality of channels corresponding to arrangement of the plurality of output speakers; a rearrangement unit configured to rearrange the plurality of mixing coefficients in the order shown in the order table; a difference calculation unit configured to calculate a differential value between two consecutive mixing coefficients among the mixing coefficients rearranged in the order; an encoding unit configured to encode the differential value calculated for each of the mixing coefficients; a symmetry table generation unit configured to generate a symmetry table showing symmetry of a positional relationship between the mixing coefficients; and a symmetry determination unit configured to determine, on the basis of the symmetry table, that, in the case where the mixing coefficient and an other mixing coefficient having the positional relationship symmetric to the mixing coefficient have the same value, the mixing coefficient and the other mixing coefficient are symmetric, wherein the encoding unit does not encode the differential value of the mixing coefficient determined to be symmetric to the other mixing coefficient.