To provide a compact loader which can be correctly fitted a mouth part of a vessel without any deformation or collapse of the mouth part or without damaging sealability thereof when the mouth part is held and loaded into a packaging machine.

In this loader of the vessel to be packaged in the packaging machine, a conveyor having a mechanism 2 for separating the vessels a one by one and holding members 4 for holding the mouth part of the vessel are disposed in a circular shape when viewed from the side, and in a manner located at a lower edge part above a rear part of the conveyor, a lattice plate 5 with a bottom part of the vessel released from the holding member placed thereon is rotated in the direction opposite to the holding member to deliver the vessel, and the vessel is inserted in a partition part of the conveyor on the packaging machine side, and the traveling speed and the rotational speed of each conveyor are synchronized with each other.