The executions came nearly three weeks after officials carried out death sentences against Shoko Asahara, the group’s mastermind, and six of his former followers.

The three attacks, which the courts said were committed to further Mr. Asahara’s bid to “control Japan in the name of salvation,” caused the deaths of 29 people. The most notorious case, the sarin nerve gas attack on the Tokyo subway system, killed 13 people and injured thousands, making it the largest attack in Japan since World War II.

Japan remains one of the few developed countries to maintain the use of capital punishment for murders by hanging. Inmates and family members are only notified of the execution on the day it is carried out. Despite international condemnation, public support for the death penalty remains high in Japan.