Process for producing immunoglobin preparation

A process for producing an immunogloblin preparation includes heating of an immunogloblin solution and is simplified and has reduced aggregates. In particular, the process comprises the step of heating an aqueous solution containing immunogloblin wherein the protein concentration is 3 (w/v)% or less in the presence of 10 (w/v)% or more of a stabilizer at a pH value of 5.2 ± 0.5 and at a conductivity of 0.01 to 1 mSi, the subsequent step of, at a pH value of 7 to 9 and a conductivity of 0.01 to 1 mSi, isoelectric focusing and/or anion exchanger treatment, and optionally together with the step of filtration with the use of a porous membrane of 1 to 100 nm average pore diameter at a pH value adjusted to 6-7.