Dumbbell

A dumbbell, wherein it is composed of a handle, a weight adjustment mechanism, and multiple sets of weight plates (3) respectively set at both axial ends of the handle, the handle consists of a rotary drum (11) and a retractable rod (12) passing through the rotary drum (11), the weight adjustment mechanism contains a turnplate (23) and a toothed disc (25) coaxially arranged with the rotary drum (11), the turnplate (23) is fixedly connected to the rotary drum (11), a driving wheel (24) is arranged in the circumferential direction of the turnplate (23), multiple grooves are set up at the end of the toothed disc (25) in the form of spiral distribution, the groove is divided into first (251) and second (252) directional sub-tracks sequentially spaced and connected along the circumferential direction, the first directional sub-track (251) is set up along the circumferential direction of the toothed disc (25), the second directional sub-track (252) is inclined at a set angle along the radial direction of the toothed disc (25) relative to the first directional sub-track (251), the retractable rod (12) is provided with multiple toothed slots (121) arranged along an axial array, and the driving wheel (24) engages with the groove and the toothed slot (121).