To provide a grouping device capable of preventing breakage of articles by allowing underpins to be correctly inserted between the articles.

In the grouping device in which the moving speed of articles A and A is regulated by successively inserting underpins 11 and 11 moving at the speed lower than that of unit conveyors 13 and 13 from a lower side into the articles A and A in the carrying direction which are continuously carried by a feed conveyor 1 consisting of the plurality of unit conveyors 13 and 13 parallel to each other, and the articles A and A between the underpins 11 and 11 adjacent to each other in the carrying direction are taken out at the carrying speed of the feed conveyor 1 by dropping the preceding underpins 11 and 11 out of the underpins 11 and 11 and drawing them between the articles A and A, the underpins 11 and 11 are correctly inserted between the articles A and A.