Provided is a slurry composition for an all-solid-state secondary battery that has excellent fluidity and preservation stability and can form a solid electrolyte-containing layer having excellent ion conductivity. The slurry composition contains a solid electrolyte, a polymer, and a solvent. The ratio of fineness of grind of the solid electrolyte, as measured by a grind gauge method based on JIS K5600-2-5:1999, relative to the average primary particle diameter of the solid electrolyte is more than 1 and less than 30.