A blow molding capable of maintaining the parison thickness distribution uniform, fabricating high-quality molded products, and improving its productivity. A parison supply device for supplying, to a blow mold, a parison discharged from an extrusion die, the parison supply device including: a pair of chucks for pinching, from above and below, a parison discharged downward from the extrusion die; and a chuck operation part for controlling an operation of pinching the parison by the pair of chucks and an operation of moving the pair of chucks. By the chuck operation part, the pair of chucks performs the operation of pinching the parison while being moved downward.

A blow molding capable of maintaining the parison thickness distribution uniform, fabricating high-quality molded products, and improving its productivity. A parison supply device for supplying, to a blow mold, a parison discharged from an extrusion die, the parison supply device including: a pair of chucks for pinching, from above and below, a parison discharged downward from the extrusion die; and a chuck operation part for controlling an operation of pinching the parison by the pair of chucks and an operation of moving the pair of chucks. By the chuck operation part, the pair of chucks performs the operation of pinching the parison while being moved downward.