PROBLEM TO BE SOLVED: To reduce the size and weight of a bed soil-charging device in which a bed soil charging hopper 11, a belt conveyer 12 for delivering the bed soil in proper portions from the hopper to drop the soil in trays below the belt conveyer, a compacting means 16 for compacting the bed soil charged in the trays, and a leveling means 17 for leveling the surfaces of the bed soil in the trays are disposed above a route for carrying the trays 8. SOLUTION: The belt conveyer 12 is formed so that the bed soil is carried in the direction opposite to the direction for carrying the trays, and the compacting means 16 and the leveling means 17 are disposed below the belt conveyer 12.