Families of the victims and representatives of local authorities gathered and observed one minute of silence in the central regions of Kiso and Otaki neighbouring the Ontake, at the same time the volcano erupted Sep 27.
Residents of both towns also placed a wreath at the foot of the mountain to "sympathise with the inhabitants of the regions and pray for the volcano to calm down", one of the organisers of the event said in statements to Kyodo agency.
On Oct 16, following the first snowfall at the top of the mountain, Japanese authorities decided to postpone the search for the six missing people until next spring, because of the risk of avalanches, landslides and low visibility.
The rescue teams had already combed most of the volcanic region and found 57 bodies.
Mount Ontake is the second highest volcano in Japan at 3,067 metres and is located about 100 km from Nagoya city.
It erupted Sep 27 when hundreds of people were hiking in the surrounding foothills and at the summit.
It is estimated that some 250 people were able to flee the area or were evacuated, 69 of whom suffered injuries, mostly bruises, fractures and burns.
The eruption was the country's worst volcanic disaster since 1926 when Mount Tokachi in northern Hokkaido blew its top, killing 144 people and injuring another 210.
As the skiing season approaches, local authorities have also launched a campaign to ensure that tourism does not suffer in the mountainous region that is home to many ski resorts.
Meanwhile, the Japan Meteorological Agency (JMA) maintains the level of volcanic alert for Ontake at three on a scale of five, meaning another eruption is possible, and access to the mountain and its surroundings is restricted.