Sol composition, aerogel composite, support member provided with aerogel composite, and heat insulator

The present invention relates to a sol composition having adequate working life, for forming an aerogel composite having excellent heat insulating properties and flexibility, wherein the sol composition for forming an aerogel composite contains at least one species selected from the group consisting of a silicon compound having a hydrolyzable functional group or a condensable functional group and a hydrolysate of a silicon compound having a hydrolyzable functional group, and silica particles having an average primary particle diameter of 5-300 nm or a specific surface area of 10-600 m 2 /g.