An object is to shorten the time for rewriting data in memory cells. A memory module includes a first memory cell, a second memory cell, a selection transistor, and a wiring WBL1. The first memory cell includes a first memory node. The second memory cell includes a second memory node. One end of the first memory cell is electrically connected to the wiring WBL1 through the selection transistor. The other end of the first memory cell is electrically connected to one end of the second memory cell. The other end of the second memory cell is electrically connected to the wiring WBL1. When the selection transistor is on, data in the first memory node is rewritten by a signal supplied through the selection transistor to the wiring WBL1. When the selection transistor is off, data in the first memory node is rewritten by a signal supplied through the second memory node to the wiring WBL1.