Abstract: Tree harvesting device is connected to a mobile vehicle by means of a jib (1) and comprises means for cutting, felling and debranching a tree. The device (2) has a general U-shaped frame comprising two side parts (3, 4), rear part (5) and an open front side (6). The cutting means (7, 8), the conveying means (11, 12) and debranching means (14, 15) being attached to the side parts (3, 4). The felling frame (19-23) is attached to the rear part (5) of a turnable means (28) in order to turn the device (2) in the transversal plane with respect to the vertical plane in the longitudinal direction of the jib (1). The felling frame (19-23) being connected to the jib (1) turnable in the vertical plane in the longitudinal direction of the jib (1).