PROBLEM TO BE SOLVED: To provide a machine body frame structure for a sulky rice transplanter, having solved such a problem that, in a conventional technique, since a chain case in the sulky rice transplanter is used for supporting rear wheels and a machine body frame is constituted of a separate member, the total weight of a body is increased, consequently a manufacturing cost is raised, while in this invention, a link frame is eliminated and the chain case is utilized as a machine body frame to lighten the total weight of the body. SOLUTION: A pair of chain cases 31.31 are installed at both right and left sides of the rear of a transmission case 6. The upper sides of the chain cases are extended upward and the chain cases are formed in an approximately triangular shape in a side view. The right and left chain cases are linked by connecting pipes 33 and 39 as connection members to constitute a part of the machine body frame. A supporting part for a lifting and lowering the link mechanism of a planting part is constituted at the rear part of the chain cases. A supporting part of an operation lever and a step receiving part are constituted on the tops of the chain cases.
