The working machine (1) has base unit (2) on which belt (12) to be worn by user is mounted. The machine is connected to working tool (3), and mounting portions (18,19) of belt is held on mounting surface of base unit. A mounting surface of friction-increasing structure is cooperated with bearing surface of the mounting portions of belt in such way that pressure surface of fastening element and fixing surface of base unit is prevented from rotational movement with respect to the base unit.
