To provide a form capable of molding a product without performing the washing-off of slag at the time of casting of concrete to form the over-hanging part of the over-hanging rod into a series surface having no unevenness.

The opening 8 allowing the over-hanging rod 1a to over hang to the outside from the side form 5 of the form A is closed by a lid plate 11 comprising an elastomer and two holes 14 matched with the upper and lower reinforcing rods 1 and 1 of the over-hanging rod 1a are provided to the lid plate 11 so as to be made openable and closable by a grooved member 15. Further, the embedding member 12 fitted to the opening 8 to fill the same is provided to the inside of the lid plate 11 to house the upper and lower rods 1 and 1 of the over-hanging rod 1a in two holes 14. When the lid plate 11 is pressed to the opening 18 from the outside to be held down by the holding-down plate 17 pressed to a pressure member 18, the whole of the opening 8 is closed by the lid plate 11.