A crystalline mixture solid composition comprising &agr;-D-glucopyranosyl-1,1-mannitol (GPM), &agr;-D-glucopyranosyl-1,6-sorbitol (GPS-6) and a small amount of &agr;-D-glucopyranosyl-1,1-sorbitol (GPS-1) and a production process therefor. The above crystalline mixture solid composition is produced by mixing a hydrophilic solvent with a solid composition or aqueous solution comprising 50 to 80 wt % of GPM, 1 to 50 wt % of GPS-6 and 0.01 to 20 wt % of GPS-1, separating solid matter from a liquid, and removing water and the solvent from the solid matter and can be obtained as a thin scale crystal.