Abstract: A production method of carbon dioxide fixing sludge fine powder as a low-carbon binder. Water is added to residual concrete or returned concrete to form it into a slurry, gravel and sand are separated and removed therefrom, fine sand is separated and removed from the sludge water by a wet cyclone to obtain concentrated sludge water, and the concentrated sludge water is dehydrated to obtain a sludge cake. The sludge cake is put into a rotary drum, hot air and highly concentrated carbon dioxide are supplied into the rotary drum, the carbon dioxide is fixed and is crushed and dried to obtain carbon dioxide fixing sludge fine powder. Alternatively, the sludge cake is crushed and fractured to obtain sludge fine powder. This sludge fine powder is exposed to highly concentrated carbon dioxide to obtain carbon dioxide fixing sludge fine powder.