Binding for fastening a boot (10) into in exercise appliance, such as into a ski (1), which binding comprises at least a support part (4), a tip part (7) installed in the support part, and a heel loop (8), of which the position of at least one or other in the support part (4) can be changed for adjusting the binding to boots of different sizes, and which heel loop (8) is installed in the support part (4) in a manner that allows turning in relation to it. The invention is implemented so that the support part (4) is hinged at its front end so that the support part is hinged around a horizontal axis, such as a hinge pin (5), which is essentially at a right angle in relation to the ski (1).