PROBLEM TO BE SOLVED: To obtain a sowing device usable for a sowing machine free from adhesion of mud on a pressing member, securely making a hole for sowing and falling the seeds into the cell by installing a specific pressing member on the sowing machine. SOLUTION: An orifice 26a for effusion of washing water is installed on the pressing member 26 of the sowing machine of a sowing plant installed with a tray supplier, a soil filling machine, the sowing machine, and a soil coverer. The orifice 26a for effusion of washing water is preferably installed at the upper part of the pressing member 26. A plurality of sprayers of washing- water or compressed air are capably installed on the outer neighborhood of the pressing member 26 of the sowing machine in the sowing plant installed with the tray supplier, the soil filling machine, the sowing machine, and the soil coverer.
