The present invention relates to a sol composition for forming an aerogel composite, wherein the sol composition is a sol composition with a sufficient pot life for forming an aerogel composite superior in thermal insulation and flexibility, and comprises: at least one selected from the group consisting of a silicon compound having a hydrolyzable functional group or a condensable functional group and a hydrolysis product of the silicon compound having a hydrolyzable functional group; and a silica particle having an average primary particle diameter of 5 to 300 nm or a specific surface area of 10 to 600 m2/g.