An absorption method includes: a step for preparing a minute passage; a main circulation step for circulating, in the minute passage, a gas as a first fluid containing a component to be absorbed and an absorbing liquid as a second fluid so that the component to be absorbed is absorbed from the gas into the absorbing liquid; and a sub-circulation step for circulating, while the gas and the absorbing liquid are circulated in the minute passage, a third fluid in the minute passage in order to raise the pressure inside the minute passage.