An extension fixture for a turning tool includes a shank, a pull rod, a clamping sleeve, and a fixing member. Thus, the fixing member presses the rotation head of the pull rod to prevent the pull rod from being rotated, thereby preventing the clamping sleeve from being loosened from the pull rod, so that the turning tool is clamped by the clamping recess of the clamping sleeve. In addition, the pull rod is positioned in the shank by the fixing member to prevent the clamping sleeve from being loosened from the pull rod, so that the turning tool is clamped in the clamping sleeve closely and will not produce a vibration during operation of the turning tool, thereby preventing the turning tool from being broken due to the vibration.