The criteria of tugboat requirement in domestic trading ports have been determined by the administrator of regional maritime affairs and port office on the basis of the regulations for the tugboat operations and management. But, there is a little confusion that the criteria of tugboat requirement and method for calculation of them are different from port to port and total power calculated on the basis of power per tugboat requirements by the number of tugs is not in accordance with total required power for the use of tug in several ports. The comparison of tugboat requirements among domestic major ports showed that it should be necessary for the criteria to be made in unified form. Because the current criteria are only on the basis q the ordinary condition with wind velocity under 10m/s, the criteria on the condition of the wind velocity over 10m/s are suggested to be necessary for the precautions against a disaster such as unexpected strong winds or typhoon.