In hot press forming a thin steel sheet K, when cooling the thin steel sheet K by supplying a refrigerant to an ejection hole (27) communicated from a supply path (28) inside a lower mold (12), precooling in which an ejection amount per unit time period of the refrigerant from the ejection hole (27) is suppressed is carried out, and thereafter, main cooling is carried out by increasing the ejection amount per unit time period.