PURPOSE: To prevent molten metal from passing around behind the back side of a hoop, by passing the hoop in inclined direction in an nonoxidizing atmosphere, and by spraying the molten metal to the under surface of the inclined hoop.

CONSTITUTION: Steel hoop 12 which is heated in an annealing furnace 11 and the surface of which has been cleaned, enters through a sealing part 13 to a plating chamber 15 of nonoxidizing atmosphere, then it is conveyed through a roll 16 upward and led through a sealing part 17, a cooling tower 18, and a sealing part 19 to the open air. In that case, the steel hoop 12 is inclined while passing from a roll 16' through a snout 14 to a roll 16. To the inclined surface of the steel hoop is sprayed molten Zn contained in Zn bath 20 by a pump 23 through a nozzle 21. The inclination angle θ (ordinary 40W60°) of the conveying line of the steel hoop and set position of the nozzle 21 depend on the height (h) of the nozzle from the bath surface, distance D of the nozzle from the roll 16, and flying distance (d) of the molten Zn sprayed from the nozzle 21. When θ is in the range 40W60°, D=h/tanθ is set larger than (d).