Focuses on a method of estimating contact force dynamically between environment and an object, which is grasped by the soft planar fingers with tactile sensors. The external contact force acting on the grasped object causes the tactile sensors to generate the displacement distributions and the force distributions. We present a method of dynamic tactual image acquisitions for both distributions at the pseudo video rate. Experimental results show the measurement of the tactual image flows due to the deflection of an object and the magnitude and orientation of force vectors operating on the finger according to the external contact force. The contact position of the external force acting on the grasped object is estimated within 15% from the tactual image distributions.