To provide a formed material containing cellulose and casein and having biodegradability of regenerated cellulose and excellent mechanical properties and to provide its production process.

This formed material has a casein content of 3-15wt.% based on the callulose and a dynamic viscoelasticity characterized by the formula, ΔTmax α≤40°C, wherein ΔTmax α is the difference between the peak temperature of the α1 peak and that of the θ2 peak of loss tangent (tanδ). It can be produced from a cuprammonium solution containing cellulose and casein and having a casein content of 3-15wt.% based on the cellulose by evaporating 20-40wt.% of the ammonia in the aqueous solution before contacting the solution with a coagulation liquid, bringing the aqueous solution to contact with a coagulation liquid and treating the coagulate with an acidic aqueous solution. The cuprammonium solution containing cellulose and casein has positive peak of the circular dichroism spectrum (CD) at 490-500nm after the evaporation of ammonia.