The mower (1) has guiding elements i.e. control levers (15), arranged between a lateral section of a mowing unit (2) and a support arm (7). An outer support arm part (10) is connected with an adjacent support arm part (9) moved around a drag axis that is directed in working and operating positions approximately transverse to driving and working directions (F). An approximately vertical alignment is carried out during a normal operation of the mower in a longitudinal extension. Force is applied on the mowing unit for a locking action of an operating resistance-dependent blocking device. The mower has a safety device arranged within a range of three point attachment device.