We propose a new capacitive proximity sensor that detects deformations of a suction cup as a tactile sense. We confirmed that one sensor module provides three applications for reliable picking and a simplified setup. The first application is the picking height decision. The second one is the placing height decision for detecting whether the grasped object is placed on the placement surface. These two applications are achieved by detecting the push-in stroke of the suction cup. The final application is detection of whether the suction cup is in partial contact or full contact with the object. This function can correct the picking posture as well as detect whether picking is possible before the pull-up motion. We also demonstrate that the partial contact position can be estimated in real time.