Abstract: A capacitance detecting device includes: first and second capacitors connected in series to each other between a power source and a detection electrode; first, second and third switches connected between terminals of the first capacitor, between the first and second capacitors, and between terminals of the second capacitor, respectively; a control circuit controlling to turn on/off the first, second and third switches, connected to a connection node between the first capacitor and the second switch, and detecting a change in a capacitance of the second capacitor; a filter circuit connected to the connection node, transmitting a potential of a frequency including switching frequencies of the second and third switches, and not transmitting a potential of another specific frequency; and a sample-and-hold circuit connected between the filter circuit and the control circuit.