Reaction vessel and method for producing polymer using said vessel

[Problem] The purpose of the invention is to provide a reaction vessel which uses an aluminum alloy vessel main body which has high thermal conductivity and in which excellent heat removal efficiency is expected, and which is capable of reducing generation of polymeric scales and microscopic condensates. [Solution] The aluminum alloy reaction vessel according to the present invention is characterized in that the inner surface of the aluminum alloy vessel main body is formed with an anodic oxide coating and an antistaining coating in this order.