PURPOSE: To obtain a casting device so as to obtain casting speed being closely analogus to the ideal curve for pouring molten metal by a simple means.

CONSTITUTION: A furnace 12 containing the molten metal 20 is provided with a float 11. A molten metal outlet 21 provided at the bottom part side of the furnace 12 and a sprue 30 provided at the bottom part of a cavity 35 in a mold 13 are connected to each other with a communicating tube 14. The float 11 can be inserted/pulled out to the inner part of the furnace from/to the upper part of the furnace 12 and the height of the molten metal surface can be changed corresponding to the inserting depth in the molten metal 20. Further, a float driving mechanism 40 for inserting the float 11 into the molten metal 20 at a prescribed speed is provided. At the time of inserting the float 11 into the molten metal 20 at the fixed speed, the cross sectional area of the float 11 is changed in the axial direction of the float 11 so that the rising speed of the molten metal surface is made fast after the molten metal surface is slow by raised at the early stage and the rising speed is made slow again at the final stage.