Capacitance detection device for detecting the capacitance of a sensor element

A capacitance detection device comprising:

• a sensor unit including at least one sensor element whose capacitance changes;
• a control line applying to the sensor element a predetermined charging voltage for detecting the capacitance of the sensor element;
• a shield line electrically shielding the control line;
• a control circuit supplying the charging voltage to the sensor element via the control line, measuring a voltage change of the sensor element when the charging voltage is applied to the sensor element, and detecting the capacitance of the sensor element based on the voltage change;
• an equipotential circuit being connected to the control line and setting a potential of the shield line equal to a potential of the control line, and
• a second equipotential circuit including an input terminal and an output terminal, generating a signal having the same potential as a signal input from the input terminal, and outputting the signal from the output terminal without drawing a current from the input terminal, wherein
• the control circuit includes a voltage input terminal for inputting a voltage of the sensor element,
• the input terminal of the second equipotential circuit is connected to the control line, and
• the second equipotential circuit generates a signal having a potential equal to the potential of the control line, and outputs the signal to the voltage input terminal.