The present disclosure a method of decoding a polar code based on a shared node, the method includes extracting an input node from target data that are data to be decoded, by an extractor, sorting the input node as one of a first node of which the pattern of the frozen bit satisfies a predetermined first reference, a second node of which the pattern of the information bit satisfies a predetermined second reference, and a third node that is not the first node and the second node, by a sorter, calculating at least one codeword candidate and at least one path metric that correspond to the input node in accordance with the sorting result by a calculator, finishing decoding the target data by iterating the extracting, the sorting as one, and the calculating of at least one path metric by a controller.