A weighting device for use with a racket includes at least one frame strip, at least one weight, and at least one screw. The frame strip is adapted for being mounted on an outer circumference of a racket frame and has a dovetail groove extending along a longitudinal direction thereof, and a plurality of through holes provided at a bottom wall of the dovetail groove. The weight has a threaded through hole and is slidably engaged in the dovetail groove. The screw is threadedly engaged with the threaded through hole of the weight and provided with an end stoppable against the bottom wall of the dovetail groove for holding the weight stationarily. Therefore, the weight can be firmly positioned and the balance of a racket using the weighting device can be quickly adjusted by adjusting the position of the weight.