A mold guiding device includes a tube having a hole in an end thereof and a threaded recess is defined in an inner end of the hole. A positioning member and a first end of a sleeve are inserted in the hole in sequence. A rod extends through the passage of the sleeve and the central hole of the positioning member and is threadedly engaged with the threaded recess in the tube. The diameter is the same as the sleeve when the sleeve is positioned in still, and is movable when the diameter of the positioning member is smaller than the passage of the sleeve.