A sliding-door handle device has an outside handle and an inside handle. The outside handle is mounted on and abuts the sliding door and has a connecting board and a pulling tab. The connecting board is shaped as an elongated strip and abuts an outer side of the sliding door. The pulling tab is formed on and protrudes perpendicularly from a front end of the connecting board such that the outside handle is formed in a T shape. The pulling tab has a pulling end and a pressing end. The inside handle is detachably connected to the outside handle via the sliding door to connect the outside handle with the sliding door and has an assembling mount.