A self-illumination dental handpiece includes a shell having a receiving space. The shell is assembled to a working room. An electricity-generation device is in the receiving space and includes first and second housings. A rotatable fan is in the second housing. The fan is coaxially connected to a magnet bar that is surrounded by a coil. The coil is electrically connected to a first conductive terminal engaged with a second conductive terminal, and the second conductive terminal is connected to a light-emitting device by a wire. A gas inlet pipe, a backflow pipe, a cooling-water pipe, and a cooling-gas pipe are in the receiving space. The pipes are positioned by a positioning member. The gas inlet pipe is connected to an external gas supply and the working room, and the backflow pipe is connected to the working room and the electricity generation device.