A semiconductor memory device includes a bank including a first cell region and a second cell region, an active signal generation unit configured to generate a first row active signal and a second row active signal having different activation periods from each other in response to a refresh command, and an address counting unit configured to count the refresh command and generate a row address, wherein a word line of the first cell region designated by the row address is activated when the first row active signal is activated, and a word line of the second cell region designated by the row address is activated when the second row active signal is activated.