A power supply circuit including a charge pump boost section which does not cause threshold reduction even if only N-channel type transistors are used as switching elements. When a boosted voltage is obtained at one end (N4) of a first capacitor (C1) in a boost section (11a), a boost control section (11b) turns on a first transistor (Q1) by applying the boosted voltage to a third capacitor (C3) to further boost the voltage. When a boosted voltage is obtained at one end (N2) of a second capacitor (C2) in the boost section (11a), the boost control section turns on a second transistor (Q2) by applying the boosted voltage to a fourth capacitor (C4) to further boost the voltage. Thus, threshold reductions of the first and second transistors (Q1, Q2) as output-side switching elements are eliminated.