A size of a charge pump circuit is reduced as well as its cost. In a positive booster charge pump circuit in an embodiment of this invention, a positive boosted voltage 2VDD generated at its first stage node is used as a gate voltage to turn on a MOS transistor that outputs a high level (VDD) of each of the first, third and fourth clock drivers. And in a negative charge pump circuit, a negative boosted voltage −VDD generated at its first stage node is used as a gate voltage to turn on a MOS transistor that outputs a high level of each of the second and fifth clock drivers.