The invention concerns a height adjustment device (1) for a handle (4) of a rollator, comprising: &mdashan inner tube (2) telescopically received in an outer tube (3), the handle (4) of the rollator being connected at the upper end of said inner tube (2), &mdasha locking assembly (10) adapted to lock the inner tube (2) in a fixed position with regard to the outer tube (3), &mdashan unlocking assembly (20) adapted to unlock the inner tube (2) from said fixed position.