Abstract: The present invention concerns a quick setting composition capable of obtaining satisfactory strength developability irrespective of the fluctuation of the ingredients in a metallurgical slag, excellent in the strength developability at cold temperature, easy for coagulation control and inexpensive as well, which contains a cement ingredient comprising portland cement and/or mixed cement, 2 to 50% by weight at the integral ratio of a quick setting agent prepared by adding 3 to 20% by weight of an alkali carbonate at an internal ratio to a mixture comprising 40 to 95% by weight of a finely powdery metallurgical slag and 5 to 60% by weight of II-type anhydrous gypsum, based on the cement ingredient, and 0.1 to 5% by weight of a coagulation controlling agent comprising an organic acid type coagulation retarder and an alkali sulfate and/or calcium salt based on the total weight of the cement ingredient and the quick setting ingredient.