Abstract: An improved lighting device generally comprises a bottom housing that has a truncate shape. The top surface of the bottom housing is connected with a supporting bracket that has mounted with a covering lid thereof. The bottom surface of the supporting bracket is provided with a mounting barrel that is connected with a motor supporting bracket. The output shaft of the driving motor is meshed with a pinion by means of a driving block. The pinion is firstly passed through the side hole of the supporting bracket, then it can be meshed with a gear of a positioning post that is disposed within a middle hole of the supporting bracket. The gear is rotationally attached to the positioning post by means of a bearing. The top end of the positioning post is projected over the central hole of the covering lid and is connected with the connector of the bulb socket. Consequently, the top surface of the gear is also projected over the central hole of the covering lid and connected further with the connecting socket.