To prevent a hose from coming off when fighting with fire with the hose connected to a hose connecting metal fitting firmly in the hose connecting metal fitting for fire fighting, which comprises a receptacle metal fitting and an insertion metal fitting which are connected to each other detachably.

The internal peripheral face of the hose connecting opening 11 of the receptacle metal fitting 10 is formed into a locking face 13 having a continuous saw tooth shape in cross sections. The locking face 13 is made to bite into the external layer section of a hose A to be locked firmly and is also pressed closely against the internal peripheral face of the hose A to form one to three locking protrusions 2 having a continuous saw tooth shape in cross sections on the external peripheral face of an expansion ring 1, which holds the hose A together with the hose connecting opening 11. The hose A is locked firmly by making the locking protrusions 2 bite into the internal layer of the hose A.