Manually operated working device having a pump, pump and pump bellows

A handheld work tool has a fuel supply system and a pump for delivering fuel from the fuel supply system. The pump (40) has an elastic pump bellows (13) to be actuated by the operator. The pump bellows (13) has a fastening section (56) at which the pump bellows (13) is fastened to a housing (41, 49). The pump bellows (13) has a base section (57) and a roof section (58), wherein the roof section (58) has a dome-shaped section (59) adjoining the base section (57) and a crown (60) adjoining thereto and closing off the dome-shaped section (59). In order to achieve a rapid return of the pump bellows (13) from the actuated to the unactuated position even at low temperatures, it is provided that the minimum wall thickness (g) of the base section (57) is at least 10% greater than the minimum wall thickness (h) of the dome-shaped section (59).