A porous body including, as a base resin, a crosslinked polymer obtained by crosslinking a polymer of an acrylic monomer and/or a styrene-based monomer. A storage modulus of the porous body is 5 kPa or more and 2000 kPa or less at 23° C., an apparent density of the porous body is 10 kg/m3 or more and 250 kg/m3 or less, and a molecular weight between crosslinking points of the crosslinked polymer is 1.0×104 or more.