The subject innovation is a vertical frame body 10 is composed of a plurality of seedling box support plate (11) on which the seedling box (1) is raised in a horizontal direction and the support frame 12 is formed hollow inside； An upper frame body 20 disposed on an upper surface of the vertical frame body 10 and having an upper coupling part 21 fitted into an upper inner side of the support frame 12 of the vertical frame body 10； The lower frame part 30 is disposed on the upper surface of the lower coupling part 31 positioned on the lower side of the vertical frame body 10 and fitted into the lower inner side of the support frame 12 of the vertical frame body 10. The upper coupling portion 21 and the lower coupling portion 31 of the lower frame body 30 are respectively formed on the upper and lower ends of the support frame 12 of the vertical frame body 10. The welding guide hole 40 is further provided through the hole, and the welding guide hole 40 has an upper coupling portion 21 and a lower frame body 30 of the upper frame body 20 through the welding guide hole 40. The lower coupling portion 31 of the welding portion 41 is welded to each other is made. The present invention, the welding guide hole is further through the upper and lower ends of the vertical frame constituting the vertical frame body, respectively, the lower coupling of the upper coupling portion and the lower frame body of the upper frame body coupled to the upper and lower parts of the vertical frame Since the welding work is performed through the additional welding guide hole, the welding part constituted by the welding work is positioned inside the welding guide hole, so that the contact area of the welding part can be widened, and thus the vertical frame body, the upper frame body, and the lower frame are formed. As well as the durability and supportability of the sieves can be greatly improved, the seedling conveyance frame can be prevented from being twisted or dropped due to vibration or s
