Semiconductor device and IC card including the same

A semiconductor memory device includes a voltage reduction circuit which reduces a power supply voltage and outputs an internal voltage, a nonvolatile memory connected to the internal voltage and a current consumption control circuit including a switch transistor and a resistor. In this case, the amount of electric current which the nonvolatile memory consumes and the amount of electric current which the resistor consumes are substantially the same. When the nonvolatile memory is in a non-operation state, the current consumption control circuit turns ON the switch transistor by a memory activation signal and consumes substantially the same amount of electric current as the amount of electric current which the nonvolatile memory consumes. When the nonvolatile memory is in an operation state, the current consumption control circuit turns OFF the switch transistor and stops electric current consumption by the resistor.