Provided is a foam sheet includes a composition including polylactic acid. The polylactic acid includes, as monomer units. D-lactic acid and L-lactic acid, and an amount of the D-lactic acid or the L-lactic acid in the polylactic acid is 98 mol % or greater. An amount of the polylactic acid is 98% by mass or greater relative to a total amount of organic matter in the foam sheet. Bulk density of the foam sheet is 0.063 g/cm3 or greater but 0.125 g/cm3 or less.