A likelihood generation device (100, 300), which is configured to generate a likelihood of each of the plurality of information bits included in a received value modulated by any modulation method and wherein the received value refers to a received symbol set including received symbols each obtained by mapping each signal point of a received signal to a two-dimensional constellation diagram, the likelihood generation device (100, 300) comprising: a similarity detection unit (101, 312) configured to: receive input of a modulation method selection signal for specifying a modulation method and the received value; detect a likelihood similarity between the information bits included in the received value based on the modulation method selection signal; and output, as a detection result, a likelihood selection signal for specifying likelihood data to be searched for in a likelihood table, and a calculation selection signal for specifying a type of calculation to be applied to the likelihood data; a likelihood table reference unit (102, 313) configured to: divide an entire likelihood distribution indicating a likelihood of each of the information bits included in the received value into a plurality of small regions in the likelihood distribution wherein the entire likelihood distribution is given in such a manner that, in the constellation diagram, an I component is set as the horizontal axis and a Q component is set as the vertical axis, and the log-likelihood ratio is used to indicate the likelihood; store the likelihood table in which only a small region having a likelihood that is different from a likelihood of another small region is registered as the likelihood data; and extract the likelihood data specified by the likelihood selection signal from the likelihood table; and a similarity processing unit (103, 314) configured to perform the type of calculation specified by the calculation selection signal for the likelihood data extracted by the likelihood table reference unit (102, 313), to thereby acquire the entire likelihood distribution to output the entire likelihood distribution. a similarity detection unit (101, 312) configured to: receive input of a modulation method selection signal for specifying a modulation method and the received value; detect a likelihood similarity between the information bits included in the received value based on the modulation method selection signal; and output, as a detection result, a likelihood selection signal for specifying likelihood data to be searched for in a likelihood table, and a calculation selection signal for specifying a type of calculation to be applied to the likelihood data; receive input of a modulation method selection signal for specifying a modulation method and the received value; detect a likelihood similarity between the information bits included in the received value based on the modulation method selection signal; and output, as a detection result, a likelihood selection signal for specifying likelihood data to be searched for in a likelihood table, and a calculation selection signal for specifying a type of calculation to be applied to the likelihood data; a likelihood table reference unit (102, 313) configured to: divide an entire likelihood distribution indicating a likelihood of each of the information bits included in the received value into a plurality of small regions in the likelihood distribution wherein the entire likelihood distribution is given in such a manner that, in the constellation diagram, an I component is set as the horizontal axis and a Q component is set as the vertical axis, and the log-likelihood ratio is used to indicate the likelihood; store the likelihood table in which only a small region having a likelihood that is different from a likelihood of another small region is registered as the likelihood data; and extract the likelihood data specified by the likelihood selection signal from the likelihood table; and divide an entire likelihood distribution indicating a likelihood of each of the information bits included in the received value into a plurality of small regions in the likelihood distribution wherein the entire likelihood distribution is given in such a manner that, in the constellation diagram, an I component is set as the horizontal axis and a Q component is set as the vertical axis, and the log-likelihood ratio is used to indicate the likelihood; store the likelihood table in which only a small region having a likelihood that is different from a likelihood of another small region is registered as the likelihood data; and extract the likelihood data specified by the likelihood selection signal from the likelihood table; and a similarity processing unit (103, 314) configured to perform the type of calculation specified by the calculation selection signal for the likelihood data extracted by the likelihood table reference unit (102, 313), to thereby acquire the entire likelihood distribution to output the entire likelihood distribution.