Provided is a likelihood generation circuit including: a first likelihood calculation circuit, which includes a table having a reception value and a likelihood associated with each other, and is configured to calculate the likelihood corresponding to the reception value by referring to the table; a second likelihood calculation circuit, which includes an operational expression for calculating a likelihood based on a reception value, and is configured to calculate the likelihood corresponding to the reception value through use of the operational expression; and a likelihood output control circuit configured to: select any one likelihood calculation circuit of the first likelihood calculation circuit and the second likelihood calculation circuit for each reception value based on a reception frequency of the reception value; stop a calculation process of another likelihood calculation circuit that has not been selected; and output the likelihood calculated by the one likelihood calculation circuit that has been selected.