A chemical conversion treatment liquid that is cobalt-free and contains a water-soluble trivalent chromium-containing substance, a water-soluble titanium-containing substance, and a water-soluble lactic acid-containing substance as essential components, the chemical conversion treatment liquid optionally containing a component at least a part of which is any of a water-soluble glycolic acid-containing substance and a water-soluble organic acid-containing substance, the water-soluble organic acid-containing substance being a water-soluble organic acid-containing substance based on an organic acid that is an organic acid other than lactic acid and other than glycolic acid, wherein when the chemical conversion treatment liquid does not contain the water-soluble glycolic acid-containing substance and does not contain the water-soluble organic acid-containing substance, a titanium-equivalent molar concentration CTi of the water-soluble titanium-containing substance, a chromium-equivalent molar concentration CCr of the water-soluble trivalent chromium-containing substance, and a lactic acid-equivalent molar concentration CLc of the water-soluble lactic acid-containing substance satisfy following Expressions to: CTi / CCr ≥ 0.5 CLc / CTi + CCr ≥ 0.40 and CLc / CTi ≤ 2.6 wherein when the chemical conversion treatment liquid contains the water-soluble glycolic acid-containing substance and does not contain the water-soluble organic acid-containing substance, the above Expressions and and a following Expression are satisfied: CLc − α × CGy / CTi + CCr ≥ 0.40 where CGy represents a glycolic acid-equivalent molar concentration of the water-soluble glycolic acid-containing substance and α represents a correction coefficient of 0.4, wherein when the chemical conversion treatment liquid does not contain the water-soluble glycolic acid-containing substance and contains the water-soluble organic acid-containing substance, the above Expressions to and a following Expression are satisfied: 0 < CCa / CLc ≤ 0.175 where CCa represents an organic acid-equivalent molar concentration of the water-soluble organic acid-containing substance, wherein when the chemical conversion treatment liquid contains the water-soluble glycolic acid-containing substance and contains the water-soluble organic acid-containing substance, the above Expressions,,, and are satisfied. the chemical conversion treatment liquid optionally containing a component at least a part of which is any of a water-soluble glycolic acid-containing substance and a water-soluble organic acid-containing substance, the water-soluble organic acid-containing substance being a water-soluble organic acid-containing substance based on an organic acid that is an organic acid other than lactic acid and other than glycolic acid, wherein when the chemical conversion treatment liquid does not contain the water-soluble glycolic acid-containing substance and does not contain the water-soluble organic acid-containing substance, a titanium-equivalent molar concentration CTi of the water-soluble titanium-containing substance, a chromium-equivalent molar concentration CCr of the water-soluble trivalent chromium-containing substance, and a lactic acid-equivalent molar concentration CLc of the water-soluble lactic acid-containing substance satisfy following Expressions to: CTi / CCr ≥ 0.5 CLc / CTi + CCr ≥ 0.40 and CLc / CTi ≤ 2.6 wherein when the chemical conversion treatment liquid contains the water-soluble glycolic acid-containing substance and does not contain the water-soluble organic acid-containing substance, the above Expressions and and a following Expression are satisfied: CLc − α × CGy / CTi + CCr ≥ 0.40 where CGy represents a glycolic acid-equivalent molar concentration of the water-soluble glycolic acid-containing substance and α represents a correction coefficient of 0.4, wherein when the chemical conversion treatment liquid does not contain the water-soluble glycolic acid-containing substance and contains the water-soluble organic acid-containing substance, the above Expressions to and a following Expression are satisfied: 0 < CCa / CLc ≤ 0.175 where CCa represents an organic acid-equivalent molar concentration of the water-soluble organic acid-containing substance, wherein when the chemical conversion treatment liquid contains the water-soluble glycolic acid-containing substance and contains the water-soluble organic acid-containing substance, the above Expressions,,, and are satisfied.