To efficiently feed a molten resin to the resin holders. An intermittently feeding device works to intermittently feed a transfer unit equipped with resin holders, and has a cam supported by a motor via a support. The cam is rotated by the motor. A cam follower of a moving block meshes with the screw of the cam, and the moving block moves along a support rail accompanying the turn of the cam. The motor rotates at a constant speed, and the transfer unit 3 is fed intermittently depending on the shapes of the cam and of the cam follower.