A plasma generating method, used in a plasma generating apparatus which includes a container, a first electrode, and a second electrode, includes: supplying a liquid in the container so that the second electrode is in contact with the liquid; in a first period, generating first plasma in a bubble generated in the liquid by applying a first voltage between the first electrode and the second electrode; supplying a first gas in the liquid in a second period after the first period; and generating second plasma in the first gas by applying a second voltage between the first electrode and the second electrode. In generating the first plasma, the first gas is not supplied in the liquid. The bubble contains a second gas.