Abstract: A semiconductor memory device includes a nonvolatile semiconductor memory including a plurality of memory cells and a plurality of word lines each connected to a page unit of memory cells, and a memory controller that controls reading of data from the memory cells. The nonvolatile semiconductor memory performs either a first read operation in which all data from the page unit of memory cells connected to a selected word line among the plurality of word lines is read, or a second read operation in which a portion of the data from the page unit of memory cells connected to a selected word line among the plurality of word lines is read, and the memory controller is configured to cause the nonvolatile semiconductor memory to perform the second read operation when data at a target physical address of a read request can be read in a single second read operation.