The invention relates to the technical field of capacitor assembling machines, in particular to a centering device. The centering device comprises a movable part and a fixed part, the fixed part comprises a first fixed plate; the movable part comprises a second fixed plate, a third fixed plate, an elastic part, an adjusting part, a connecting part and a centering part; the second fixed plate is fixedly connected with a movable part of the capacitor assembling machine and the third fixed plate; the elastic part and the adjusting part sleeve the connecting part, one end of the elastic part is connected with the third fixed plate, and the other end of the elastic part is connected with the adjusting part; the adjusting part is detachably connected with the connecting part, the connecting partpasses through the third fixed plate, the second fixed plate and the first fixed plate in order from top to bottom, and is fixedly connected with the centering part, and the centering part is arranged at the lower portion of the first fixed plate; and the movable plate can move up and down relative to the fixed part. The centering device adds a capacitor aluminum foil righting structure prior toriveting of a capacitor lead so as to fundamentally solve the quality hidden trouble caused by capacitor lead riveting deviation and improve the production quality to a certain extent.