A foam sheet includes a polylactic acid resin composition that includes a polylactic acid resin. The polylactic acid resin includes 98% mol % or greater of D-lactic acid or L-lactic acid that is a constituent monomer unit of the polylactic acid resin. An amount of the polylactic acid resin is 98% by mass or greater relative to a total amount of organic matter of the foam sheet. The foam sheet has a bulk density of 0.063 g/cm3 or greater and 0.250 g/cm3 or less. A surface roughness Sq (root mean square height of the surface) of the foam sheet defined by ISO 25178 is 7 μm or less.