The invention concerns a bath lift device (1) for raising and lowering persons into or out of a bathtub comprising two independent parts that can be easily separated: - a fixed part (10) including a chassis (11-14) adapted to rest, in use, on a floor of the bathtub, said chassis (11-14) comprising two tubular upright elements (11) parallel to each other, extending, in use, in a close to vertical direction, - a movable part (20) including a seat frame (21) supporting a seat plate (22) and a backrest (23), said seat frame (21) being moveable upward and downward relative to the chassis (11-14) via a lifting means (24) and being slideably mounted onto said two upright elements (11), characterized in that said moveable part (20) comprises two pairs of guiding rollers (25) rotatably connected to said seat frame (21), each pair being slideably mounted onto one upright element (11) and the guiding rollers (25) of each pair being disposed, in use, on opposite sides of said one upright element (11).
