Abstract: Provided is a device for suppressing pitch angle fluctuation in the main body of a seaplane, and enabling operation in higher waves. A float (3) is divided in the length direction thereof into a base member (3a) linked at the center thereof to a seaplane main body (2), and a turning member (3b) located at the lengthwise end of the base member, the turning member being capable of turning between a normal position for being positioned along the length direction of the base member, and an active position for being positioned higher than the length direction of the base member, a linking means (K(6)) being provided between the base member and the turning member to link the two members together in a manner enabling the members to rotate relative to each other, the linking means urging the turning member toward the normal position.