A rapid mold replacing device for use in molding machine includes: a mold having lateral walls at two ends disposed with a pair of bolt slots; a pair of fastening members, having a locking member connected at an outer side of each fastening member, and protruded with a locking bolt, and a top surface of each locking member having an unlocking slot; and an unlocking mechanism, disposed on a top surface of the elevation seat and having at least one first retractable driving device, and a pair of unlocking blades capable of being synchronously driven by the first retractable driving device; when the pair of unlocking blades are inserted in or released from the pair of unlocking slots, the mold can be formed in an un locked or a locked status to the mold.

A rapid mold replacing device for use in molding machine includes: a mold having lateral walls at two ends disposed with a pair of bolt slots; a pair of fastening members, having a locking member connected at an outer side of each fastening member, and protruded with a locking bolt, and a top surface of each locking member having an unlocking slot; and an unlocking mechanism, disposed on a top surface of the elevation seat and having at least one first retractable driving device, and a pair of unlocking blades capable of being synchronously driven by the first retractable driving device; when the pair of unlocking blades are inserted in or released from the pair of unlocking slots, the mold can be formed in an un locked or a locked status to the mold.