According to a certain embodiment, the semiconductor device includes a circuit block and a clock circuit configured to supply a clock signal to the circuit block at a specific timing. The clock circuit includes an output circuit configured to provide the clock signal to the circuit block, and a control circuit configured to control the timing at which the output circuit provides the clock signal. A threshold voltage of at least a transistor in the output circuit using the clock signal as input/output signals is a first threshold voltage, and a threshold voltage of a transistor configuring the control circuit is a second threshold voltage higher than the first threshold voltage.