Antitumor agents containing as the active ingredient staurosporin derivatives represented by general formula (I) or pharmacologically acceptable salts thereof wherein R1 is hydrogen, hydroxyl, or lower alkoxy; R?2 and R3¿ are each independently hydrogen, substituted or unsubstituted lower alkyl, substituted or unsubstituted lower alkenyl, substituted or unsubstituted lower alkynyl, substituted or unsubstituted aryl, a substituted or unsubstituted heterocyclic group, halogeno, nitro, formyl, or the like; R4 is hydrogen or the like; and R?5 is NR11AR12A¿ (wherein R?11A and R12A¿ are each hydrogen, substituted or unsubstituted lower alkyl, or the like), with the proviso that both R?2 and R3¿ are not hydrogen.