To provide a levee plastering machine with a simple and low-cost structure, which enables the selection of the presence or absence of the function of making a working section follow an original levee, without depending on the operation and skill of a worker.

A hydraulic cylinder 15, which is decoupled by a piston and which has the pressure of one cylinder chamber set higher than that of the other cylinder chamber, is attached, in such manner that the working section 40 is urged toward the working object surface, to a link mechanism which enables the working section 40 to move in the direction of being brought into contact with/separated from the working object surface, during the operation of at least the working section 40. The inside of the hydraulic circuit of the hydraulic cylinder 15 is provided with a valve which reduces the pressure of the cylinder chamber when the pressure of the cylinder chamber with the pressure set higher reaches fixed pressure or above, a bypass circuit for bypassing the pressure-reducing valve, and a change-over valve for determining whether the hydraulic pressure passes via the valve or via the bypass circuit.