PURPOSE: A useful anticancer showing an anticancer action by bonding directly to an active site of protein C kinase to inhibit its enzymatic activity, containing an isoquinoline derivative as an active ingredient.

CONSTITUTION: An anticancer containing an isoquinoline derivative shown by the formula I [A is amine residue selected from group shown by the formula II, -NH-(CH2)2-NH-R3 and group shown by the formula III; R1, R2, R4 and R5 are the same or different lower alkyl; R3 is H or lower alkyl] and its acid addition salt as active ingredients. When it is used, the active ingredient compound can be directly used as it is, but usually it is blended with an excipient, diluent, etc., pharmaceutically manufactured by a conventional procedure into an injection, oral or mucosal application, etc., and used. The compound shown by the formula I, for example, is synthesized by reacting an isoquinolinesulfonic acid halogenide derivative shown by the formula IV (X is halogen) with a compound shown by the formula H-A.