To provide a chuck device capable of strongly clamping work and a tool, and improving the efficiency of chucking work by increasing a boosting rate for boosting driving force imputed from an inputting member.

This chuck device 1 is provided with a worm gear system 5 reducing rotational driving force imputed from the inputting axial member 4, a second gear system 6 driving a screw shaft member 46 in an axial direction by the rotational driving force transmitted from the worm gear system 5, and a converting system 7 for converting the driving force in axial direction transmitted to the screw shaft member 46 to drive a pair of claw members 3 symmetrically in right and left.