To obtain a corrosion preventive agent for a washing liquid which does not have corrosion resistance to tungsten and is optimum for metal washing by including ≥1 kind of the compounds selected from triazoles, polyethylene imine and polyamine sulfone into this agent.

This corrosion preventive agent for metals includes the compounds selected from the triazoles containing one amino group or thiol group, the polyethylene imine and the polyamine sulfone expressed by the formula (in the formula, R1, R2 are H, CH3, C2H5 or CH2C6H5, X- is an anionic group and n is 30 to 200). More preferably, the triazoles are 3-aminotriazole; the polyethylene imine is of 300 to 10,000 in molecular weight. The polyamine sulfone is of hydrogen in R1 and R2. The washing liquid composition not having the corrosion resistance to the metals and more particularly the tungsten may be provided by mixing this preventive agent with the washing liquid.