A band saw machine includes a machine frame unit with a longitudinal guideway, a cam follower movable along the guideway, a wheel mount movable with the cam follower between closer and remote positions relative to a first wheel mounted on the machine frame unit, a biasing member disposed to bias the wheel mount to the remote position, a second wheel mounted on the wheel mount, a band saw blade trained on the wheels, and an actuating shaft with a cam end which engages the cam follower. The wheel mount can be kept in the closer position with a friction force that counteracts the biasing force of the biasing member by turning the actuating shaft so as to permit replacement of the band saw blade.