A ration filling device for champignon machine. Relate to champignon machine structure field. The utility model provides a structure is exquisite, stability good and long service life, can carry out a ration filling device for champignon machine of the ration filling of essential oil during the use automatically. Ration filling device establishes in the water tank, and be located on the high liquid level (HLL), ration filling device includes fixing base, rotating electrical machines, rotary disk, a plurality of piston and a piston drive assembly, a plurality of piston cylinder bodies and a plurality of filler port have been offered on the rotary disk, the filler port is established the bottom of piston cylinder body, and one the piston cylinder body and function is in storing an essential oil, the piston cylinder body is the uncovered form in top, piston and piston cylinder body looks adaptation and sliding connection are in the piston cylinder body, the accidental injury of effectively having solved the manual interpolation complex operation that exists among the prior art and having caused because of the corrosivity of essential oil.