All were executed on Friday, July 6, 2018.
Asahara and five of the six executed were implicated in the subway attack. The date of their executions is not known.
Kiyoe Iwata, whose daughter died in the subway attack, says the execution of Asahara gave her "peace of mind".
The cult was preparing for the apocalypse, and had more than 10,000 members in Japan alone.
Chizuo Matsumoto, the cult's leader who went by the name Shoko Asahara, was the first to be hanged, media said as it broke into regular programming to report the news.
"The attacks carried out by Aum were despicable and those responsible deserve to be punished. However, the death penalty is never the answer", said Hiroka Shoji, East Asia Researcher at Amnesty International.
Aum Shinrikyo, a Japanese doomsday religious movement, founded in 1984, is recognized as a terrorist group by a number of states, including Russia, EU countries, the United States, Canada and Kazakhstan.
Cult members have said they believed Asahara's prophesy that an apocalypse was coming and they alone would survive it.
Cult guru Shoko Asahara, left, of Aum Shinrikyo walks with Yoshihiro Inoue, then a close aid, in Tokyo. They had been convicted of a series of crimes including a 1995 sarin gas attack that killed 13 people and sickened more than 6,000 others on the Tokyo subway system. "But I did feel the world had become slightly brighter", said Atsushi Sakahara, a film director who was injured in the sarin attack at Tokyo's Roppongi station. At its peak, Asahara had tens of thousands of followers worldwide.
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"We should have heard more stories from the people involved and deepened discussions in society to get to the bottom as to why such crimes related to religion happened", Ogawara said.
"I would like to apologize to the victims", he said. The cult's activities in various parts of Japan sparked anxiety years after the sarin gas attack.
Until his execution, there was little information about Asahara. The killing was eventually linked to the cult.
The cult also used sarin in 1994, releasing the gas in the central Japanese city of Matsumoto on a summer night in an attempt to kill three judges set to rule on the cult.
Though concerns about the Aum had already been raised, the attack prompted a massive crackdown on the cult's headquarters in the foothills of Mount Fuji, where authorities discovered a plant capable of producing enough sarin to kill millions.
He was the leader of the 40,000-strong Aum Shinrikyo cult, which sneaked plastic bags full of sarin nerve gas onto packed subway cars and burst them during the Monday morning rush hour.
Asahara himself was arrested in May 1995, and indicted on 17 charges ranging from murder to illegal production of weapons and drugs.
About 180 members were sentenced to varying prison terms. By 2006, he had exhausted the appeals process.
Why has the execution been so delayed? In 2007 a senior AUM disciple and his followers left Aleph to launch a splinter group called Hikari no Wa (Circle of Rainbow Light). The two groups have around 150 and 1,500 followers respectively, according to Japanese media.