PURPOSE: To enhance the quality and yield of a hot dip galvanized steel sheet by galvanizing a steel sheet and hot dip galvanizing the galvanized steel sheet without carrying out annealing.

CONSTITUTION: A steel sheet 2 unwound from a payoff reel 1 is degreased in a degreasing vessel 4 an galvanized in a galvanizing vessel 5. The galvanized steel sheet is hot dip galvanized in a hot dip galvanizing vessel 6 without carrying out annealing. The hot dip galvanized steel sheet is wound around a tension reel 10 usually after passing through an alloying furnace 7 and a temper rolling mill 8. The quality and yield of the hot dip galvanized steel sheet can be enhanced.