The present invention provides a compound having a specific chemical structure and having an exceptional inhibitory action on EZH1 and/or EZH2 activity, or a pharmaceutically acceptable salt thereof. A compound having a 1,3-benzodioxole structure represented by general formula (I), a pharmaceutically acceptable salt thereof, or a pharmaceutical composition containing such a compound. (R1, R2, R3, R4, R5, R6, and V in formula (I) are each as defined in the specification.).