A machine of the rotary blade type in which a rotor having discal members fixed mounted on its opposite end surfaces is rotatably and eccentrically mounted in a casing. At least a telescopic blade comprising a plurality of blade portions is mounted for sliding motion in a blade groove formed to extend through the rotor and the discal members are formed with grooves for supporting and guiding the telescopic blade. Support means are arranged in two rows on the outsides of the discal members for positioning respective blade portions, the support means being parallel to each other and mounted rotatably. Two telescopic blades can be disposed in two parallel blade grooves formed to extend through the rotor.