The purpose of the Phase 2 study is to evaluate immunogenicity and safety of three different doses of candidate hexavalent vaccine in comparison to co-administration of EupentaTM Inj. and Imovax® Polio in separate injections at four weeks after completion of three-dose primary series at 6-10-14 weeks of age when administered to 336 healthy infants and thereby to select the optimal dose of the candidate vaccine.