A chemical treatment solution for coating a zinc-based plated steel sheet having a zinc-based plating layer containing 0.1 to 22.0 mass % of aluminum, the chemical treatment solution comprising: a molybdenum acid ion; a pentavalent vanadium ion; an amine; an oxoate of group 4 element; and a compound selected from the group consisting of a diammonium hydrogen phosphate, an ammonium dihydrogen phosphate, and triammonium phosphate, wherein: the amine has a molecular weight of 80 or less, a molar ratio of molybdenum to vanadium in the chemical treatment solution is 0.4 to 5.5, a molar ratio of the amine to the vanadium in the chemical treatment solution is 0.3 or more, a content of a hydrophilic resin in the chemical treatment solution is at most 100 mass % based on a total amount of the vanadium and the molybdenum in the chemical treatment solution, a total content of fluorine derived from a fluorine ion or a fluorometal ion in the chemical treatment solution is at most 30 mass % based on the total amount of the vanadium and the molybdenum in the chemical treatment solution, and a content of silicon derived from a silanol group in the chemical treatment solution is at most 50 mass % based on the total amount of the vanadium and the molybdenum in the chemical treatment solution. a molybdenum acid ion; a pentavalent vanadium ion; an amine; an oxoate of group 4 element; and a compound selected from the group consisting of a diammonium hydrogen phosphate, an ammonium dihydrogen phosphate, and triammonium phosphate, wherein: the amine has a molecular weight of 80 or less, a molar ratio of molybdenum to vanadium in the chemical treatment solution is 0.4 to 5.5, a molar ratio of the amine to the vanadium in the chemical treatment solution is 0.3 or more, a content of a hydrophilic resin in the chemical treatment solution is at most 100 mass % based on a total amount of the vanadium and the molybdenum in the chemical treatment solution, a total content of fluorine derived from a fluorine ion or a fluorometal ion in the chemical treatment solution is at most 30 mass % based on the total amount of the vanadium and the molybdenum in the chemical treatment solution, and a content of silicon derived from a silanol group in the chemical treatment solution is at most 50 mass % based on the total amount of the vanadium and the molybdenum in the chemical treatment solution. the amine has a molecular weight of 80 or less, a molar ratio of molybdenum to vanadium in the chemical treatment solution is 0.4 to 5.5, a molar ratio of the amine to the vanadium in the chemical treatment solution is 0.3 or more, a content of a hydrophilic resin in the chemical treatment solution is at most 100 mass % based on a total amount of the vanadium and the molybdenum in the chemical treatment solution, a total content of fluorine derived from a fluorine ion or a fluorometal ion in the chemical treatment solution is at most 30 mass % based on the total amount of the vanadium and the molybdenum in the chemical treatment solution, and a content of silicon derived from a silanol group in the chemical treatment solution is at most 50 mass % based on the total amount of the vanadium and the molybdenum in the chemical treatment solution. <EOS>