According to one embodiment, a memory system includes a first decoder that decodes read information read from a nonvolatile memory that records therein a multidimensional error-correcting code to output hard decision decoding information of each symbol; a second decoder that performs soft decision decoding in units of component codes for the read information using a soft-input value to output soft decision decoding information of each symbol; a soft-decision-decoding information memory that retains the soft decision decoding information of each symbol; and a soft-input-value specifying unit that obtains the soft-input value of each symbol using the read information and the hard decision decoding information or the soft decision decoding information, and the soft-input-value specifying unit obtains an initial value of the soft-input value using the read information and the hard decision decoding information, and outputs an output decode word obtained as a result of the soft decision decoding when the output decode word is determined to be correct.