PURPOSE: To enable concrete to be poured in an arbitrary spot, by a method wherein a first auxiliary conveyor is disposed in a direction crossing at the position of a tripper and under a main conveyor, and second auxiliary conveyors are installed on the opposite end sides of the first auxiliary conveyor.

CONSTITUTION: Ready mixed concrete is delivered to a main conveyor 2 through an elevating conveyor 1, and is conveyed in the direction of the width of a dam. The main conveyor 2 is provided with a tripper 9, the concrete is discharged in arbitrary spot located in the direction of the width of the dam, and a second auxiliary conveyor 5 is installed in a direction crossing a first auxiliary conveyor in the position of the tripper 9. The ready mixed concrete is delivered to a first auxiliary conveyor 4, the concrete is conveyed to either of the two second auxiliary conveyors 5 and 6, and is placed in a final given spot. This, even if a dam has a wide area and is hight, enables rapid placing of the concrete.