By processing an object to be processed with the disclosed multifunctional surface treatment composition, the occurrence of turbidity and sedimentation occurring during low-temperature storage is prevented, antibacterial properties are imparted, odor-resistance, water repellency and oil repellency are improved, and frictional resistance is reduced. The composition contains: octadecyl dimethyl (3-trimethoxysilylpropyl) ammonium chloride and/or octadecyl dimethyl (3-triethoxysilylpropyl) ammonium chloride, amidoamine oxides and alcohol, and water.
