A backpack type working machine has a main unit including a power source and a backpack band detachably attached to the main unit, for a worker to backpack the main unit and perform an operation. The back pack has a pad member including a belt-like cushion material and a belt-like band body extending along the pad member. The band body includes an upper end belt-like part branched from an upper end part of the pad member and an upper end joint for connecting the upper end belt-like part to the main unit. The main unit has an attachment for attaching thereto the upper end joint. When the upper end joint is attached to the attachment, the upper end part of the pad member comes into contact with the main unit from a worker side and is held downward.