To provide a suit for competitive swimming effective for straightening the posture of the swimmer, improving the motor function and increasing the propelling power.

The waist dimension on the pattern is set to 45-55% of the nude dimension of the waist of the swimmer for the swimming suit and the 1st front body and back body are made of a material having high stretch strength. The angle θ between the 1st and 2nd switch lines on the pattern of the 1st back body is set to about 105-125° to bend the body above the waist of the trunk of the swimmer backward. Accordingly, the posture of the swimmer is kept to a straight form to reduce the resistance of water to the body of the swimmer, improve the motor function and increase the propelling power. Allowance is formed on each part near the broadest muscle of back, near the upper part of buttock and the side line of the 2nd front body.