A charge pump circuit has a first controller (in the embodiments, switches SW1a to SW4b and charge transfer transistors P2b to P4b) that increases and decreases the number of step-up units actually operated according to the specified step-up factor; and a second controller (in the embodiments, an inverter INV4) varies the step-up input voltage in one of the step-up units according to the specified step-up factor. With this configuration, it is possible to vary the step-up factor finely and in a wide range without unnecessarily increasing the number of step-up stages.