A method of designing a golf club head, including the steps of using a golf club head model and a golf ball model both of which are composed of a plurality of finite elements; impacting the head model against the ball model; and measuring a time period T2 in which the face of the head model is in contact with the ball model and a time period T1 from the time of contact between the head model and the ball model until the time when a vertical force acting on the face of the golf club head model takes a peak value; setting the ratio of the time period T2 to the time period T1 high and increase a frictional force acting in a direction in which the backspin of a golf ball decreases and a period of time in which the frictional force acts.