A constant voltage generator is comprised of a band gap reference circuit, a current supply circuit, a starting circuit and a voltage-current conversion circuit, and the starting circuit is further comprised of a first and second load elements, a first transistor which is connected to the first load element, a second transistor of which current capability is larger than the first transistor and which shares the voltage of the base with the first transistor and is connected to the second load element, a first resistor which is connected to the first transistor, and a second resistor which is connected to the second transistor, and the output of the voltage-current conversion circuit is input to the connection point between the second transistor and the second resistor, and the current at the connection point between the second load element and the second transistor controls the current supply circuit.