A blow molding device and a blow molding method are disclosed that can blow-mold a container with a handle without requiring a handle inserter that inserts a handle into a blow molding section. A blow molding method for blow-molding a container with a handle includes heating a preform (2) that is held by a heating transfer jig (370), transferring the preform from the heating transfer jig to a blow transfer jig (420), and transferring the blow transfer jig in a state in which a handle (500) is held by the blow transfer jig to be adjacent to the preform in a transfer direction.