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 moveable 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) and in that said guiding rollers (25) are fixedly positioned with regard to the backrest (23) so as to define a four-points connection between said moveable part (20) and said fixed part (10) and so that said moveable part (20) is installed on said fixed part (10) by only a combination of tilting and sliding displacements of said seat frame (21).Linvention concerne un dispositif élévateur pour baignoire (1) pour soulever et abaisser des personnes dans ou hors dune baignoire, lequel dispositif comprend deux parties indépendantes qui peuvent être facilement séparées : - une partie fixe (10) comprenant un châssis (11-14) adapté pour reposer, lors de lutilisation, sur un plancher de la baignoire, ledit châssis (11-14) comprenant deux éléments verticaux tubulaires (11) parallèles entre eux, sétendant, lors de lutilisation, dans une direction proche de la verticale, - une partie mobile (20) comprenant un cadre de siège (21) supportant une plaque de siège (22) et un dossier (23), ledit c
