Compounds having a diphenylmethane skeleton are superior in broad utility and stability, and are useful as a protecting reagent (anchor) of amino acid and/or peptide in the liquid phase synthesis and the like of a peptide having a C-terminal etc., which are of a carboxamide(-CONHR)-type, and in organic synthetic reaction methods (particularly peptide liquid phase synthetic methods), and may be contained in a kit for peptide liquid phase synthesis.