It is disclosed here that a protein with a heat-labile specific binding activity can be stabilized with a saccharide compound with regard to the binding activity. To heat-stabilize the protein, it is mixed with a saccharide compound in a liquid suspension and the suspension is then dried to produce a solid that contains the protein and the saccharide. The saccharide compounds that possess the protein heat-stabilization activity include monosaccharides, disaccharides, polysaccharides, alkylated monosaccharides, alkylated disaccharides, alkylated polysaccharides, monosaccharide alcohols and alkylated monosaccharide alcohols.