Abstract: The present invention relates to an extension rod assembly for a screw driving tool, which includes a base, a slide sleeve, a rear compression spring, a front compression spring, a fixing ring and a magnetic iron. The rear and front compression springs are disposed in the slide sleeve. When pushing the slide sleeve toward the tool head, the magnetic iron at end of the slide sleeve can provide a magnetic force to make the tool head pick up a screw to be screwed easily, besides, when pushing the slide sleeve toward the rod, the tool head will be caused to slide out of the slide sleeve, so as to facilitate replacement of the tool head.