Hyeon Soo Lim, 60, was arrested in the capital Pyongyang after he travelled there in January for humanitarian work.
The Toronto-based pastor, who is of South Korean origin, was shown at a news conference earlier confessing to a plot to overthrow the government and set up a “religious state”.
North Korea bans religious activity.
The authorities periodically detain foreigners for religious or missionary activity and similar cases have seen staged public confessions from prisoners.
Media captionDr John Nilsson-Wright, head of the Asia Programme at Chatham House says Soo Lim has been very unlucky
Canada’s foreign ministry said in a statement it was “dismayed at the unduly harsh sentence… particularly given his age and fragile health.” It added that Canadian officials were seeking access to Mr Lim.
Mr Lim was sentenced after a 90-minute trial at the North Korean Supreme Court.
He was convicted of joining the US and South Korea in an anti-North Korea human rights “racket” and fabricating and circulating false propaganda materials tarnishing the country’s image.
He was also accused of funding and helping “defectors” to escape, in some cases through Mongolia.
The pastor entered and left the court in handcuffs flanked by two public security officers in uniform, the Associated Press news agency reports.
Read more at BBC.