At around 6 p.m. CST, crews were pouring water on a single-storey commercial building on 105 Main St., close to where the show was shot for six seasons.
A Corner Gas movie was filmed in Rouleau this summer. In the TV show, the town is called Dog River.
It's not believed there were any injuries, but the building, which is home to a prosthetic limb design company, was destroyed.
Corner Gas has been an important tourist draw for the town in recent years.
The fire burned close to some of the old sets, but they were not damaged.