First and second current drivers are connected to one end of corresponding first and second write bit lines, respectively, and the first and second write bit lines are directly connected, at the other end, to a common line. The first and second current drivers receive a first power supply voltage and the ground voltage, while the common line receives a second power supply voltage higher than the ground voltage and lower than the first power supply voltage. The first and second current drivers cause a current for data writing to flow in a first direction based on a voltage difference between the first power supply voltage and the second power supply voltage, and cause a current for data writing to flow in a second direction based on a voltage difference between the second power supply voltage and the ground voltage.