The dynamics of swimming is considered to be hydrodynamics which acts on a swimmer and the water around the body. Propelling force generated by hand is a resultant force of lift and drag. The propelling force can be divided into two optimal kinds, the maximum mode of propelling force and the minimum mode of energy consumption by lift-drag curves of hand. Driving angles and tilt angles of hand were calculated in a balance state of propelling forces of hand and drag forces of the whole body by utilizing with published data of hand on a quasi-steady state. As a result, the followings were acquired : The hand plane should be almost perpendicular to the direction of motion in each mode. Concerning the maximum mode of propelling force, such as in a competitive swimming, the hand should be driven along the body axis to the advancing direction for drag forces to be used entirely. However, for the minimum energy consumption in swimming, sculling action of hand is important to utilize not only drag force but also lift force.