A composite material of the invention is a mixture of cellulose microfibers having a carboxyl group content of 0.1 to 3 mmol/g and a moldable polymeric material selected from the group consisting of a biomass-derived polymer and a petroleum-derived polymer. The biomass-derived polymer is preferably polylactic acid or pulp. The cellulose microfibers are preferably present in an amount of 0.01% to 60% by mass. Another composite material of the invention is a mixture of cellulose composite microfibers and a moldable resin, the cellulose composite microfibers being obtained by adsorbing a surfactant onto cellulose microfibers having a carboxyl group content of 0.1 to 3 mmol/g.