In accordance with an embodiment, a substrate treatment method includes bringing a first metallic film on a substrate into contact with a first liquid, mixing a second liquid into the first liquid, and bringing the first metallic film or a second metallic film different from the first metallic film into contact with a liquid in which the first liquid and the second liquid are mixed together to etch the first or second metallic film. The first liquid includes an oxidizing agent, a complexing agent, and water (H2O) of a first content rate to etch the first metallic film. The second liquid includes water (H2O) at a second content rate higher than the first content rate after the etching has started.