Abstract: Device (1) for installing/removing a seal (12) for an injection group of a coffee machine, comprising a body (2) which is elongate along a longitudinal axis (XX?), a handle (3) for gripping the body (2) and two rows of lugs (4), one of which is arranged at one end and the other of which is arranged at the other end of the elongate body (2). Each lug (4) of a row, which is radial relative to the body (2), is arranged around the body (2) on a centre circle which passes through the longitudinal axis (XX?) of the body (2), and each lug (4) of a row has a face (41) which is called the internal face and which is directed towards the lugs (4) of the other row and which forms a helical ramp (5) which is inclined to allow, in the positioned state of the ramps (5) of a row of lugs (4) in bearing contact with inclined surfaces forming ramps with complementary shapes, and, in the state in which the body (2) is rotated about its longitudinal axis (XX?), axial displacement of the body (2).