There is provided with a decoding apparatus for decoding a low-density parity check code defined by a parity check matrix, includes: a first operation unit configured to carry out a row operation for each row of the parity check matrix; a calculation unit configured to calculate a reliability coefficient with respect to establishment of a parity check equation defined by said each row, respectively; a second operation unit configured to carry out a column operation for said each row; and a controller configured to iteratively execute one set which includes respective processing by the first operation unit, the calculation unit and the second operation unit and omit the processing by the first operation unit and the calculation unit for a row for which the reliability coefficient has satisfied a threshold.