Abstract: A three-dimensional (3D) lamp tube includes a first electrode terminal and a second electrode terminal formed at both ends of the 3D lamp tube respectively, and a plurality of straight tube sections disposed between the first and second electrode terminals, and a bent section is disposed between two straight tube sections, and the first electrode terminal is extended upwardly from one of the straight tube sections and through the plurality of bent sections, and bent along an external periphery of the first electrode terminal to produce an arc 3D structure, and finally extended downwardly from another straight tube section to the second electrode terminal, so that the space and volume occupied by the 3D lamp tube can be concentrated to improve the drawback of the conventional lamp tube that can only be applied to a large planar lamp socket and to replace the conventional light bulb.