To provide a joint facilitating the laying work of a panel body and dispensing with a hose and a floor heating panel using this joint.

This joint comprises an outer cylinder 27, an inner cylinder 23 to be inserted into the outer cylinder 27, stopper mechanisms 24, 25, 30, and 32 for preventing the inner cylinder 23 from dropping out from the outer cylinder 21, and an annular seal member 29 for sealing the inside of the outer cylinder 27 to the outside of the inner cylinder 23. The outer cylinder 21 and the inner cylinder 23 are relatively movable in the axial direction while keeping the sealed state between the both by the seal member 29.