PURPOSE: To separate a formed synthetic resin molding without peeling off the skin layer of the molded part by a small loading force by inserting a separating means forcefully along a molded part line after placing a molded part line to be cut on a placing stand and fixing it temporarily by a push- pressing means.

CONSTITUTION: After separating a molded part sheet to be cut into a molded part line 4 by another separator in advance, at first, a transfer member 58 is brought near the one end side of a placing stand 52 after operating a transfer means 55 and also the placing stand 52 is raised up by a cylinder 61. Then, a side frame 24 is put in turning movement in the placing stand 52 side while holding the molded part line 4 and the placing stand 52 is lowered at the same time when the holding of the molded part line 4 is released. Then, after transferring the transfer member 58 until touching to a hit stop turn out means 73, the molded part line 4 is push-pressed by plural push-pressing means 65, 66 so as to be fixed temporarily. Thereafter, the molded part 2 to be cut is separated one by one in order from the molded part line 4 by inserting the separating member 72 forcefully along the molded part line 4 after operating the separating means 71.