Stiffness is an important index to know the quality of a cell. While there have been a couple of works to evaluate the cell stiffness in real time by combining a micro fluid chip with electric impedance based cell counters, we can not see what is really happening in the channel after all. The challenge of this paper is to develop a system capable of evaluating the cell stiffness in real time and of checking the measured data toward 100% guarantee. The proposed system is composed of a real time vision and a micro channel. It enables us to capture the data in 5 [msec/cell] in maximum and later to examine whether all data are appropriately obtained or not, by utilizing logged vision data taken at each event. We explain the basic procedure for evaluating the cell stiffness and confirm the effectiveness of the idea through experiments.