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

A sol composition for forming an aerogel composite, the sol composition comprising:

• at least one silicon compound 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 at least one polysiloxane compound having a structure represented by the following formula (B):
• wherein R1b represents an alkyl group, an alkoxy group, or an aryl group;
• R2b and R3b each independently represent an alkoxy group;
• R4b and R5b each independently represent an alkyl group or an aryl group;
• and m represents an integer of 1 to 50;
• and
• a silica particle having an average primary particle diameter of 5 to 300 nm, or having a specific surface area of 10 to 600 m2/g.