To achieve a human like grasping with a multi- fingered robot hand, the grasping force should be controlled without using information from the grasped object such as its weight and friction coefficient. In this study, we propose a method for detecting the slip of a grasped object using the force output of Center of Pressure (CoP) tactile sensors. CoP sensors can measure the center position of a distributed load and the total load applied on the surface of the sensor, within 1 ms. These sensors are arranged on the fingers of the robot hand, and their effectiveness as slip detecting sensors is confirmed in tests of slip detection during grasping. Finally, we propose a method for controlling grasping force to resist tangential force applied to the grasped object using a feedback control system with the CoP sensor force output.