A majority decision circuit includes: a majority decision unit configured to compare first data with second data to decide whether one of the first data and the second data has more bits with a first logical value; and an offset application unit configured to control the majority decision unit so that the majority decision unit decides, in a case when the number of bits with the first logical value among the first data is equal to the number of bits with the first logical value among the second data, that the first data have more bits with the first logical value if offset is a first setting value in a first phase and decides that the second data have more bits with the first logical value if the offset is a second setting value in a second phase.