To provide an apparatus for curing concrete which can form a temperature environment almost equal to the outside of the apparatus on completion of curing.

The apparatus is equipped with a main body accommodating a concrete product to be cured, steam piping disposed in the lower portion inside the main body and supplying steam into the main body and steam discharge piping discharging the steam from the main body. A solenoid valve is disposed at the steam discharge piping. The apparatus is equipped with outdoor air introducing piping which is disposed in the lower portion inside the main body and introduces outdoor air into the main body, and the outdoor air is introduced into the main body through this piping by a sirocco fan. When the sirocco fan operates in this constitution, the solenoid valve is opened, while the solenoid valve is closed when the sirocco fan does not operate.