PURPOSE: To uniformly stir molten metal and to improve stirring efficiency by arranging undurating part having different and downs on surface at outer circumferential part of bar-like stirrer in apparatus for forming molten metal into semi-solidified slurry by rotating the bar-like stirrer.

CONSTITUTION: The stirrer 16 is descended with a hydraulic cylinder 10 and an opening hole part at lower side of a vessel 1 is closed and gas is sucked and evacuated and after heating the stirrer, vessel and a lower vessel, the mol ten metal W is supplied. Temp. control of the molten metal W is executed, and by rotating the stirrer 16, dendritic crystal line structure is crushed to make the semi-solidified metal slurry. In the part in the range SU of upper side of the stirrer 16, the molten metal W is stirred with comparatively weak stirring force and in the part of lower side part SL, the molten metal W is stirred with comparatively intensive stirring force. In the part SU, the stirring force is weakened because of the part having distance l2, l3 between the projec tion parts 20a, 20b, and in the part SL, the stirring force is not weakened. By this method, the stirring force of the stirrer is vertically changed and as the whole, the uniform stirring can be executed.