Abstract: The present invention relates to an immersion microscope objective (10) for inspecting a sample (S) in an immersion medium (M), comprising: at least one concave minor (3), at least one optical element (1) comprising an aspherical surface (2) facing the at least one concave minor (3), and an internal space (4) arranged between the at least one concave minor (3) and said aspherical surface (2), said internal space (4) being configured to be filled with an immersion medium (M) such that the immersion medium (M) contacts the at least one concave minor (3) and the aspherical surface (2). According to the present invention, the aspherical interface (2) is shaped such that the working distance (7) of the immersion microscope objective (10) varies by less than 1% when the refractive index n of said immersion medium (M) is increased or decreased by at least 0.025.