A method of manufacturing a semiconductor device sealed in a cured silicone body by placing a semiconductor device into a mold and subjecting a curable silicone composition that fills the spaces between said mold and said semiconductor device to compression molding, wherein the curable silicone composition comprises the following components: (A) an organopolysiloxane having at least two alkenyl groups per molecule; (B) an organopolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; (C) a platinum-type catalyst; and (D) a filler, wherein either at least one of components (A) and (B) contains a T-unit siloxane and/or Q-unit siloxane. By the utilization this method, a sealed semiconductor device is free of voids in the sealing material, and a thickness of the cured silicone body can be controlled.