TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Property: The temperature dependency ratio of the sealing layer is 50 or less, and is set as the ratio of storage elasticity modulus of the sealing layer at -20 degrees C and storage elasticity modulus of the sealing layer at 100 degrees C. Preferred Composition: The content of silicon atom in the hardened material of sealing layer is 10-60 wt.%. The sealing layer contains silicon-type particles (A) having core alkoxysilane condensate shell structure obtained by coating silicon-type particles (A1) with shell component (A2) obtained by adding and condensing alkoxysilane, and silicone resin. The silicon-type particles further comprises shell component (A3) provided on shell component (A2). The shell component (A3) contains alkoxy silane condensate obtained by condensing monofunctional alkoxysilane compound (a) of formula: R12O-Si(-R13)(-R15)-R14 (I), bifunctional alkoxy silane compound of formula: R22O-Si(-OR23)(-R25)-R24 (II), bifunctional alkoxy silane compound of formula: R32O-Si(-R33)(-R35)-R34 (III), and/or tetrafunctional alkoxy silane compound of formula: R42O-Si(-R43)(-OR45)-R44 (IV). The shell component (A2) consists of alkoxysilane condensate obtained by condensing bifunctional alkoxy component (II), trifunctional alkoxy silane compound (III) and/or tetrafunctional alkoxy saline compound (IV). The content of silicon-type particles, shell component (A2) and shell component (A3) is 40-98 weight%, 1-40 weight% and 1-30 weight%, respectively. The sealing layer is obtained by hardening curable composition containing organopolysiloxane (B) having 2 or more alkenyl group and organopolysiloxane (C) having 2 or more hydrosilyl group. The component (B) is an organopolysiloxane having 2 or more alkenyl groups, and has three-dimensional network structure having tetrafunctional structural unit of formula: SiO4/2 (V). The terminal of the three-dimensional network structure is blocked by monofunctional structural units of formulae: Ra1(Ra2)2SiO1/2 (VI) and (Ra2)3SiO1/2 (VII). The component (C) is an organo-hydrogen-polysiloxane having 2 or more hydrosilyl group in a molecule, and has three-dimensional network structure having tetrafunctional structural unit (V). The terminal of the three-dimensional network structure is blocked by monofunctional structural units of formulae: Rb1(Rb2)2SiO1/2 (VIII) and (Rb2)3SiO1/2 (IX).R12=alkyl;R13-R15,R24,R25,R35=monovalent organic group;R22,R23,R32-R34,R42-R45=monovalent alkyl;Ra1,Ra2=(un)substituted monovalent hydrocarbyl other than alkenyl;andRb1,Rb2=H or (un)substituted monovalent hydrocarbyl other than alkenyl.