NOVELTY - A sealing material (2,4) comprises composite resin (A) containing polysiloxane segment (A1) having silanol group and/or hydrolyzable silyl group and vinyl polymer segment (A2) having alcoholic hydroxyl group, and polyisocyanate (B). The content of the polyisocyanate is 5-50 wt.% with respect to the total solid content of the sealing material. The composite resin contains 10-50 %mass of the segment (A1), and has silicon-containing structural unit (I) or (II).    USE - Sealing material for solar cell module and light emitting diode (all claimed). Uses include but are not limited to display board, light source for image reading, traffic light, unit for large sized display and backlight of mobile telephone.    ADVANTAGE - The sealing material has excellent weather resistance, yellowing resistance, crack resistance, light resistance and heat-and-moisture resistance over a long period of time.    DETAILED DESCRIPTION - A sealing material comprises composite resin (A) containing polysiloxane segment (A1) having silanol group and/or hydrolyzable silyl group and vinyl polymer segment (A2) having alcoholic hydroxyl group bonded by bond of formula (III), and polyisocyanate (B). The content of the polyisocyanate is 5-50 wt.% with respect to the total solid content of the sealing material. The composite resin contains 10-50 %mass of the segment (A1), and has silicon-containing structural unit of formula (I) or (II).    R1-R3=1-6C alkyl, 3-8C cycloalkyl, aryl, 7-12C aralkyl, group having polymerizable double bond chosen from -R4-CH=CH2, -R4C(CH3)=CH2, -R4OCOC(CH3)=CH2 or -R4-OCOCH=CH2, at least one being group having polymerizable double bond;and    R4=single bond or 1-6C alkylene.    The silicon atom bonded with oxygen atom comprises a portion of the polysiloxane segment.    DESCRIPTION OF DRAWING(S) - The drawing shows the structure of a solar cell module.    Protection sheet (1)    Sealing materials (2,4)    Solar cell group (3)    Back surface side protective material (5)