The invention provides a semiconductor device capable of reducing wasteful power consumption. The semiconductor device of the invention does not require a refresh operation, and includes memory circuits for storing data, arranged in a matrix form, first signal lines for reading data from the memory circuits, second signal lines for transferring a signal that controls connection between the memory circuits and the first signal lines, a sense amplifier circuit for reading and determining data by detecting a potential change or a current change in the first signal lines, and a mitigating means for mitigating the potential change or the current change in the first signal lines during a period in which the sense amplifier circuit is being activated.