A separation method including: an absorption process absorbing a desired component in a starting material gas into an absorption liquid by bringing the starting material gas and the absorption liquid into contact with each other inside an absorption unit; a regeneration process releasing the desired component from the absorption liquid and regenerating the absorption liquid by heating the absorption liquid, which absorbed the desired component in the absorption process, in a regeneration unit; a post-regeneration separation process separating the mixed fluid, which is the gas of the desired component released in the regeneration process and the regenerated absorption liquid, into the desired component gas and the absorption liquid; and a compression process compressing the starting material gas prior to the absorption process and the regeneration process.