A lens module includes a base; a focusing ring rotatably mounted to the base and having at least one driving portion formed on a torus thereof, the driving portion having at least two positioning portions and at least one inclined portion in connection with the two positioning portions, the two positioning portions being located at different radial positions of the ring body; and a combination holder being fitted onto the focusing ring to be rotatable on an internal sidewall the focusing ring, the combination holder having at least one convex portion contacting against one of the at least two positioning portions, the combination holder being combined with a lens barrel that a lens set is received. Accordingly, while the focusing ring is rotated, the combination holder is axially moved to change the axial distance between the combination holder and the base, finally attaining the focusing effect.