Temperature‐responsive change in pKa of tertiary amines that are immobilized in the cross‐linked LCST polymer chains (temperature‐responsive amine gels) is applied to the separation and recovery of CO2 gas. Adsorption and desorption behaviors of CO2 gas on the temperature‐responsive amine gels are experimentally investigated using a temperature‐controlled gas‐liquid contact reactor with the slurries of the gels. Based on the control of the swelling volume of the temperature‐responsive gels via temperature swing, pKa of the amines in the gels was controlled. Influences of monomer composition in the gels and solvent composition in the slurry on the performance of CO2 recovery were investigated.