A stair assistance device includes a rail unit having a toothed rail which has a teeth row. A base movably is engaged with the toothed rail and includes a pulley unit and a brake unit. The pulley unit is movable relative to the rail unit. The brake unit includes a roller which is engaged with the teeth row. A brake member is movably engaged with or disengaged from the roller. A grip unit is movably connected to the base and drives the brake member. The grip unit includes a grip which extends outward relative to the rail unit. The users hold the grip unit to control the brake member to be disengaged from the roller. The stair assistance device moves the users by the cooperation between the roller and the teeth row.
