A tool for removing and replacing a light bulb includes a long handle rod, a chuck at an upper end of the handle rod, and an operating mechanism at a lower end of the handle rod for actuating the chuck. The chuck includes an arm holder, bearing brackets, chuck arms pivotally supported by the bearing brackets, tension springs for closing the chuck arms, a seat pad for receiving and supporting a top surface of the glass sphere of the light bulb, guide bars for opening the chuck arms, and a movable bar-holder-block connected to the operation mechanism for supporting the guide bars. When the movable bar-holder-block is pulled downward by the operating mechanism, the upper end portions of the chuck arms are operatively opened away from one another.