There is provided an exhaust gas treatment system including a CO 2 recovery unit with further enhanced energy efficiency. An exhaust gas treatment system (1) of the present invention includes: a CO 2 recovery unit (10) including a CO 2 absorption column (11), an absorbing solution regeneration column (16), and a reboiler (21); and an exhaust gas heat exchanger (5) provided on a gas upstream side of the CO 2 recovery unit (10). Heat exchange is performed between process condensate discharged from the CO 2 absorption column (11) and steam condensate discharged from the reboiler (21) in a heat exchanger (22). The heated process condensate is fed to the absorbing solution regeneration column (16). Heat exchange is performed between the cooled steam condensate and exhaust gas in the exhaust gas heat exchanger (5) so that the steam condensate is heated while the exhaust gas is cooled.
