A boost circuit includes multiple switching circuits connected in parallel. Each switching circuit includes first through third transistors and a resistor. The first transistor, the resistor, and the second transistor are serially connected between first and second nodes. The third transistor is connected between the source of the first transistor and the second node. A conductance Gm (S) of the second transistor and a resistance r (Ω) of the resistor are respectively configured to be within ranges of 1≦Gm≦1000 and 7×Gm−1.6≦r≦170×Gm−1. Since the first transistor having a high breakdown voltage is turned on by turning on the second transistor, variations in turn-on time of the boost circuit are reduced.