PROBLEM TO BE SOLVED: To provide an antivirus/antibacterial agent that is an aqueous solution in which a silicon compound having an antibacterial functional group is dissolved and has excellent temporal stability and a deodorant effect.SOLUTION: An aqueous solution of a silicon-containing compound contains 0.1 to 1.0% by weight of a silicon-containing compound represented by a formula (1) and 0.1 to 1.0% by weight of β-cyclodextrin. Preferably, it is an aqueous solution of a silicon-containing compound in which the compound represented by the formula (1) is octadecyldimethyl(3-triethoxysilylpropyl)ammonium chloride. (R1 is a C6 or more hydrocarbon group； R2 and R3 each independently represent a lower hydrocarbon group； R4 represents a divalent lower hydrocarbon group； R5 to R7 each independently represent a lower alkyl group or a lower alkoxy group； and X represents a halogen ion or an organic carbonyloxy ion.)SELECTED DRAWING: Figure 5
