Abstract: An unbalance vibrator comprises a drive shaft mounting unbalance weights, one of which is fixed stationary while the other one is turnable with respect to the drive shaft, and a mechanism for adjusting their mutual position made in the form of a rod spring-loaded in an axial direction and fitted in the movable unbalance weight so as to be movable radially, and adapted to interact with the other unbalance weight. The fixed unbalance weight is made in the form of a cylindrical sleeve having radial holes provided on its inside cylindrical surface. The movable unbalance weight is made in the form of at least a part of a cylinder arranged inside the cylinder, the rod being mounted so as to be engageable in one of the radial holes provided on the inside cylindrical surface of the sleeve.