To provide an inexpensive exhaust treatment apparatus having a high removal rate of a contaminated substance in exhaust.

The exhaust treatment apparatus includes an air intake port 3c communicating with an exhaust port 2a of an exhaust source 2 for discharging the exhaust containing the contaminated substance; a supply port 3e supplied with ultra-high temperature and pressure steam 12; a supply and exhaust mixture flow channel 3b for communicating with the supply port and the air intake port to pass the exhaust, and the ultra-high temperature and pressure steam; a steam ejector 3 having an outlet of the supply and exhaust mixture flow channel; a condensing device (vacuum tank 4, cooling tank 5) for condensing the mixture exhaust of the exhaust discharged from the outlet of the steam ejector, and the ultra-high temperature and pressure steam; and an exhaust blower 6 for sucking the exhaust from the condensing device to exhaust to the air outside.