The objective of the work reported here was to study on the subject of detaching torsional resistance among some properties(tension, torsion and cutting) taking part in detaching of tomatoes in the case of harvesting operation. And as the factors to represent the detaching torsionalresistance, the torsional moment and the total twisting angle of tomato peduncle was used in order to facilitate for study. The kinds of tomatoes used were Chico and H1370. As the main experimental results, the maximum torsional moment(T_<max>)and the total twisting angle(φ_<T0>) were considerably influenced by the kinds of tomatoes, and those values of H1370 were slightiy larger than those of Chico. The values of a/b never had a really large influence upon the values of T_<max> and φ_<T0>, but the weight of tomatoes was proportional to the values of T_<max> and φ_<T0>. It is clear that it is necessary to give a rotary movement with about 550 degree in order to harvest tomatoes.