Disclosed is a surface treatment liquid containing no chromium compound, which is capable of imparting a zinc-based material with adequate corrosion resistance without coating, namely adequate bare corrosion resistance. Specifically disclosed is a surface treatment liquid for zinc-based metal materials, which contains the following component (A) and component (B): (A) at least one metal element selected from the group consisting of Ti, Zr and Hf; and (B) at least one compound selected from the group consisting of allylamino compounds, imino compounds, amino polysaccharides, amino-modified phenols and derivatives of them. The total concentration of the metal elements of the component (A) is 500-2000 mg/L, and the total concentration of the compounds of the component (B) is 300-3000 mg/L.