To provide a soft start circuit capable of obtaining a high-accuracy soft start time. The soft start circuit is equipped with a constant current source, an output terminal which outputs a soft start voltage, a ground terminal, a first transistor which is connected between the constant current source and the ground terminal and has a gate and a drain both short-circuited, a second transistor which is connected between the constant current source and the output terminal and receives a clock signal at a gate thereof, and a capacitor connected between the second transistor and the ground terminal.