An ellipticine derivative of the formula [I]: ##STR1## wherein R is a substituted lower alkyl group, a substituted or unsubstituted lower alkoxy group or a heteromonocyclic group, or a pharmaceutically acceptable salt thereof, which show excellent antitumor activity, less side effects, less toxicity and/or high solubility in water and are useful as antitumor agent, and a process for preparing the same.