The device for preparing mold-sand, comprising a mixer under the form of a fixed pan containing mixing elements under the form of shares and of vortex heads, and an assembly for controlling the mold-sand mix moisture fixed on a wall of said pan above the level of the shares, wherein the assembly for controlling the mold-sand mix moisture comprises a case for forming a specimen and fixed obliquely on the wall of the fixed pan, at one end of which a plunger with a built-in moisture probe and an air cylinder are mounted, and its other open end located inside the mixer being provided with a periodically-operated butterfly valve serving to fill the case with mold-sand, with an additional air cylinder.