PURPOSE: To provide an automatic sealing device of a vessel lid which can automatically fit with the continuous movement to the body of a vessel with lid to increase the fitting workability and the productivity and which has no anxieties of breakage in the lid and the body on fitting without adopting conventional rotary type or turning-over type and further, reduces the ratio of inferior goods.

CONSTITUTION: A suction-taking out part 10 is provided to take out a plurality of stacked lids 8 one by one and a pneumatic conveyor 12 is equipped to transfer them by jet air at the lid 8 after having taken out them. And further, a positioner 14 is provided to place the lid 8 transferred by the pneumatic conveyor 12 in a specified inclined state and a transfer means 16 is attached to transfer the body 6 in order to force the body 6 to get in contact with the inside of the lid 8 at the positioner 14. Moreover, rollers 18 are provided to fit the lid 8 by pressing it on transferring, while placing the lid 8 on the upper part of the body 6 by the transfer means 16.