PURPOSE: To obtain an immunoactivator useful for preventing various infectious diseases and tumors and for preventing and treating diseases caused by aging, comprising an oxazopyrroloquinoline as an active ingredient.

CONSTITUTION: An oxazopyrroloquinoline shown by the formula (R is the same as R' of α-amino acid shown by the formula R'-CH(NH2)-COOH) and/or a salt thereof is used as as an active ingredient. The compound is properly blended with a surfactant, excipient, colorant, preservative, coating auxiliary, etc., and pharmaceutically manufactured to give the objective substance. The substance is pharmaceutically manufactured into oral administration state such as capsule, tablet, powder, etc., and a parenteral administration state such as injection or solution. Further a sustained release preparation is effective. The compound shown by the formula extremely activates B cell, T cell and macrophage activity participating in immunity. The compound shown by the formula is obtained by reacting pyrroloquinoline-quinone or a salt thereof with an amino acid, methylamine, etc., in the presence of oxygen.