The reaction products of thiocyanate and salt of carboxylic acid were found to be useful as a rapid fixing agent of silver halide emulsion. The products were prepared by the reaction of thiocyanate salt and salt of aliphatic or aromatic carboxylic acid such as sodium hydrogen citrate, sodium hydrogen succinate, and potassium hydrogen phthalate in the presence of acid or carbonate salt at a temperature in the neighborhood of 75°C for about 2.5 hours. The products were more stable to light and humidity than thiocyanate. The hygroscopicity of the products decreased by 10-20 percent as compared with that of thiocyanate salt. The fixing time with the products was shorter than that with thiosulfate salts. The clearing time was reduced in the order of nNH₄SCN·NaC₄H₃O₄, nNH₄SCN·NaC₄H₅O₆, nNH₄SCN·NaC₄H₅O₄, nNH₄SCN·KC₈H₅O₄, nNH₄SCN·Na₂C₆H₆O₇.