PURPOSE: To make changing of core carriers possible without stopping a molding device by providing a traveling frame between a mold pass line and a core preparing station and an inverting frame between the latter and a core carrier preparing station.

CONSTITUTION: Clamping cylinders 29 are extended and operated to grip a core carrier A20 with gripping plates 30 from top and bottom directions and to disengage the carrier A20 from a press contact plate 10; thereafter the plate 10 is retreated by a press contact cylinder 9. An inverting frame 27 is inverted 180° to move a carrier B20 and to bring the rear surface of the carrier B20 in tight contact with the plate 10. Said carrier is surely gripped by the engagement with pawl members. In succession, the carrier B20 is disengaged from the plates 30, whereby the changing of the carrier A20 with the B20 is completed. Thereafter, the new carrier B20 is used, and a traveling cylinder 22 is extended and operated to move the carriage B20 together with a traveling frame 8, and the plate 10 to the position facing the mold 3, where the core held in the carrier B20 is shifted to the mold 3 side.