To provide a resin composition for sealing exhibiting good mold-releasability from a mold for molding to enable successive molding without obstacle; and to provide a semiconductor device sealed with such the resin composition for the sealing.

The resin composition for the sealing comprises (A) an epoxy resin, (B) a phenol resin-based curing agent, (C) an inorganic filler and (D) a silicone, satisfying the relation of (θ0-θ100)/θ0≤0.1 (wherein, θ100 is a contact angle of water on the metal plate surface obtained by repeating 100 times of processes comprising subjecting the resin composition for the sealing to transfer molding on a metal plate under a condition of 175°C and 2 min, and pealing the resultant molded product therefrom; and θ0 is a contact angle of the water on the metal plate before the transfer molding). The semiconductor device is obtained by sealing a semiconductor element with the cured product of the resin composition.