PURPOSE: To provide the seedling-planting device having a frame structure capable of reducing the error of seedling planting operations, improving the seedling-planting operability and simplifying constituting members.

CONSTITUTION: The seedling-planting device is characterized by disposing a pipe-shaped main frame 7 extended in the lateral direction, disposing a laterally directed driving shaft 17 for transmitting a power from a power-taking shaft 8 on the side of a traveling frame to plural planting cases 9 on the outside of the main frame 7, connecting and fixing each planting case 9 to the main frame 7, connecting and fixing a feed case 6 to the main frame 7, and continuously connecting the rotation support points of grounding stands 36, 36 and the support brackets of drawing markers 38, 38 to lids 34, 34 for closing openings at both the side ends of the main frame 7, respectively.