A conductive movable body opens and closes an opening portion formed in a conductive opening forming body. The movable body has a front edge portion positioned in a front side in the closing direction of the movable body. The opening portion has an opposed edge portion opposed to the front edge portion. The sensor is arranged in a layout body corresponding to one of the opening forming body and the movable body, and is arranged in one of the front edge portion and the opposed edge portion. The sensor is capable of detecting a conductive object-to-be-detected on the basis of a change of a capacitance between a sensor electrode and the object-to-be-detected coming close to the sensor electrode. A guard electrode is provided between the layout body and the sensor electrode. An electric potential of the guard electrode is kept equal to an electric potential of the sensor electrode or kept at a fixed rate with respect to the electric potential of the sensor electrode. Accordingly, it is possible to prevent an improper operation of a capacitance type sensor in the opening and closing apparatus.