<p>[PROBLEMS TO BE SOLVED] To provide a chuck unit for improving a view of an operator and surely restoring a swing pipe pushed out against urging of an elastic member associated with movement of a driver bit to a steady position. [MEANS FOR SOLVING PROBLEMS] A chuck unit (1) has a coil spring (11) for urging the swing pipe (10) wound around the pipe (10). Thus, the chuck unit (1) has a projecting part reduced so that the view of the operator for an object to be tightened can be improved when the unit (1) is attached to a tip of a handheld screwdriver (50) or the like for use.</p>
