In order to examine the effect of loading rate on the holding force and the diameter of cylindrical object at maximal holding force, the subject was requested to grasp the cylindrical object at various loading rateS. The loading rate produced a large difference in holding force among cylinders. The force to hold the cylinder with a diameter of 20-25 m was influenced considerably by the loading rate. In the loading rate ranging from 5 to 600 N/min, the maximal holding force increased logarithmically with the loading rate. The relationship between the diameter of cylinder at maximal holding force (Dmax) and the loading rate (dF/dt) within range from 10 (or 20 N/min) to 600 N/min can be expressed using the following equation: D max=a dF/dt -b These results in the present study proposed the necessity to introduce the loading rate against the operating hand to the design of the operating parts of machines or tools.