A contents-filling apparatus for use in a bag packaging machine. The apparatus comprises a reversing device including a rotating device for rotating intermittently a main rotating member (9,10) around an axis thereof in one direction and for stopping the rotating member at a first and a second positions, and a pair of gripping members (16,17) attached to the rotating device and being capable of gripping and releasing said vessel (Y). The gripping members are designed to stop at a gripping stop position where said gripping members can grip a vessel in an upright state when said main rotating member stops at the first stop position, and stop at a reversal stop position where said vessel is held in a nearly inverted state when said main rotating member stops at the second positions. The apparatus further comprises a reversal stop position regulating device (45) for regulating said reversal stop position, an empty vessel carrying-out device provided at an empty vessel discharging position on the way along which said gripping members returns from said reversal stop position to said gripping stop position, said empty vessel carrying-out device receiving an empty vessel and transferring it to downstream process; and a gripping member opening/closing apparatus for making said gripping members close to grip a vessel and for making said gripping members opens, thereby discharging the empty vessel towards an empty vessel carrying-out device.