The present invention relates to an alkoxysilyl group 
epoxy compound, a method for producing the same, a composition including the same, and a hardening material, wherein the compound has excellent 
heat resistance, particularly exhibits a low coefficient of 
thermal expansion (CTE) and a high 
glass transition ascending effect in the composition and / or exhibits excellent 
flame retardance in the hardened material, and a separate 
silane coupling agent is not needed. By means of the present invention, provided are: an 
epoxy compound having a core including an 
epoxy group and at least one alkoxysilyl group which is an S1 
substituent independently selected from the group consisting of 
Chemical Formula S11 to S15 or an S2 
substituent independently selected from the group consisting of 
Chemical Formula S21 to S25; a method for producing the alkoxysilyl-based epoxy compound produced through the epoxy ring-opening reaction and alkoxysilylation of a start material; an epoxy composition including the epoxy compound; a hardened material of the same; and a use of the same. The hardened material which is a composite of the composition including the novel alkoxysilyl group epoxy compound by means of the present invention has the improved 
chemical bond of the alkoxysilyl group from the epoxy compound and a filling agent. 
Coupling and bonding efficiency is also improved when a composite is produced by means of the 
coupling and bonding of alkoxysilyl groups of the epoxy compound having the alkoxysilyl group. Accordingly, excellent 
heat resistance properties such as a low CTE and a high 
glass transition temperature are exhibited in the composite, and / or excellent 
flame retardance is exhibited in the hardened material.