A fluid treatment method reduces a concentration of a first component included in a fluid-to-be-treated. A fluid treatment apparatus reduces a concentration of a first component included in a fluid-to-be-treated. A concentration of a second component differing from the first component is reduced in the fluid-to-be-treated in order to obtain a first fluid. The first fluid passes through at least part of an adsorption unit in order to obtain a second fluid. The adsorption unit is capable of adsorbing both the first component and the second component and has at least an ability to adsorb the first component that is temperature dependent. A third fluid pass through a portion of the adsorption unit through which the first fluid has passed. The third fluid has a concentration of the second component that is lower than in the fluid-to-be-treated and a temperature that is higher than the fluid-to-be-treated.