Finland imports most of its gas from Russia but says it can cope with the disruption
Finland has been refusing to pay for its supplies in roubles. But it also follows an announcement that Finland will apply for Nato membership.
Gasum said the move was "regrettable" but there would be no disruption to customers after the 04:00 GMT cut-off.
Despite its invasion of Ukraine on 24 February, Russia continues to supply gas to many European countries.
After Western powers sanctioned Russia over the war, Russia said "unfriendly" countries must pay for gas using the Russian currency, a move the EU considers blackmail.
Reliance on Russian energy is a contributing factor in the cost-of-living crisis faced by many consumers.
Finland imports most of its gas from Russia but gas accounts for less than a tenth of the country's energy consumption.
"It is highly regrettable that natural gas supplies under our supply contract will now be halted," Gasum CEO Mika Wiljanen said in a statement.
"However, we have been carefully preparing for this situation and provided that there will be no disruptions in the gas transmission network, we will be able to supply all our customers with gas in the coming months," he added.
Asked about the matter, a Kremlin spokesman said "it is obvious that nobody is going to deliver anything for free".
Last Sunday, Russia also cut electricity supplies to Finland. It had threatened retaliation should Finland apply to join Nato.
In a separate development, Russia's state-owned oil company Rosneft said on Friday that former German Chancellor Gerhard Schröder had informed them he would no longer serve on their board.
Mr Schröder has faced increasing public outrage over the lucrative role. He has refused to criticise Russia's President Vladimir Putin, who he counts as a personal friend, over his decision to invade Ukraine.
-- Courtesy of BBC News