To provide a concrete finished product which uses a cement paste (concrete sludge generated during centrifugal forming of a concrete finished product), separated by centrifugal force as an industrial waste conventionally without being effectively utilized, as concrete mixing water.

The residue which is generated during centrifugal forming, containing a cement component, an additive, a high-performance water reducing agent component, etc. is utilized as the concrete mill mixing water under the control of concentration by a gamma radiation transmission-type densitometer. Further, this mixture of the concrete and the cement paste is centrifugally formed into the concrete finished product.