A shoulder hanging type and backpack type grass trimmer handle folding device includes a joint installed at the middle of a main body for positioning a handle, and the joint includes a lower casing a fixed base having an upper casing at a lower end of the fixed base and corresponding to the lower casing for fixing the main body, and the upper end has a containing slot for axially connecting the handle a positioning element for unfolding the handle to transversally position at the fixed base, folding the handle to longitudinally attach to and position at both sides of the main body, so as to achieve the effects of folding and unfolding the device easily, reducing the volume of the device, and facilitating the storage and transportation of the device.
