To improve the waveform of the output voltage of a triangular wave generating circuit.

A first constant current source 10 supplies charging currents to the second terminal of a first capacitor C1 whose first terminal is grounded. The first terminal of a second capacitor C2 is grounded, and a first switch SW1 is installed between the second terminal of the first capacitor C1 and the second terminal of the second capacitor C2. A second constant current source 12 supplies currents to the second capacitor C2, and a second switch SW2 is installed on the current path of the second current source 12. A third constant current source 14 extracts currents from the first capacitor C1 and the second capacitor C2. When an output voltage Vout appearing in the second terminal of the first capacitor C1 reaches a predetermined upper limit voltage VH, a switch control part 20 turns on the first switch SW1, and turns off the second switch SW2, and when the output voltage Vout decreases to a predetermined lower limit voltage VL, the switch control part 20 turns off the first switch SW1, and turns on the second switch SW2.