A memory circuit comprising: a bistable circuit configured to write data; a nonvolatile element (MTJ1, MTJ2) configured to store data written in the bistable circuit in a nonvolatile manner, and restore data stored in a nonvolatile manner into the bistable circuit; and a control unit configured to store data written in the bistable circuit in a nonvolatile manner and cut off a power supply to the bistable circuit when it is determined that a period not to read data from or write data into the bistable circuit is longer than a predetermined time period, and store no data written in the bistable circuit in a nonvolatile manner and make a supply voltage for the bistable circuit lower than a voltage during a period to read data from or write data into the bistable circuit when it is determined that the period not to read or write data is shorter than the predetermined time period, wherein the memory circuit is characterized in that: the control unit is further configured to determine whether the period not to read data from or write data into the bistable circuit is longer than the predetermined time period, when determining that the period not to read data from or write data into the bistable circuit is longer than the predetermined time period, the control unit is further configured to store data written in the bistable circuit in a nonvolatile manner, and to cut off the power supply to the bistable circuit, and when determining that the period not to read or write data is shorter than the predetermined time period, the control unit is further configured not to store data written in the bistable circuit in a nonvolatile manner, and to make the supply voltage for the bistable circuit lower than the voltage during the period to read data from or write data into the bistable circuit. a bistable circuit configured to write data; a nonvolatile element (MTJ1, MTJ2) configured to store data written in the bistable circuit in a nonvolatile manner, and restore data stored in a nonvolatile manner into the bistable circuit; and a control unit configured to store data written in the bistable circuit in a nonvolatile manner and cut off a power supply to the bistable circuit when it is determined that a period not to read data from or write data into the bistable circuit is longer than a predetermined time period, and store no data written in the bistable circuit in a nonvolatile manner and make a supply voltage for the bistable circuit lower than a voltage during a period to read data from or write data into the bistable circuit when it is determined that the period not to read or write data is shorter than the predetermined time period, wherein the memory circuit is characterized in that: the control unit is further configured to determine whether the period not to read data from or write data into the bistable circuit is longer than the predetermined time period, when determining that the period not to read data from or write data into the bistable circuit is longer than the predetermined time period, the control unit is further configured to store data written in the bistable circuit in a nonvolatile manner, and to cut off the power supply to the bistable circuit, and when determining that the period not to read or write data is shorter than the predetermined time period, the control unit is further configured not to store data written in the bistable circuit in a nonvolatile manner, and to make the supply voltage for the bistable circuit lower than the voltage during the period to read data from or write data into the bistable circuit. the control unit is further configured to determine whether the period not to read data from or write data into the bistable circuit is longer than the predetermined time period, when determining that the period not to read data from or write data into the bistable circuit is longer than the predetermined time period, the control unit is further configured to store data written in the bistable circuit in a nonvolatile manner, and to cut off the power supply to the bistable circuit, and when determining that the period not to read or write data is shorter than the predetermined time period, the control unit is further configured not to store data written in the bistable circuit in a nonvolatile manner, and to make the supply voltage for the bistable circuit lower than the voltage during the period to read data from or write data into the bistable circuit.