A milling tool (1, 1') for chip-removing machining comprising: - a tool body (2, 2') being rotatable around a central rotation axis (C 1, C 1 '), the tool body comprising at least one insert seat (3, 3') with a plurality of side contact surfaces (3a, 3b, 3a', 3b'), - at least one indexable cutting insert (4, 4') including an insert centre axis (C 2, C 2 ') around which the indexable cutting insert (4, 4') has a rotational symmetry, wherein the indexable cutting insert (4, 4') has a plurality of side support surfaces (4a, 4b, 4a', 4b'), which are situated around the insert centre axis (C 2, C 2 ') and arranged to be supported by the side contact surfaces (3a, 3b, 3a', 3b') of the insert seat (3, 3'), - at least one internal indexing mechanism (6, 6') being arranged to displace the indexable cutting insert (4, 4') between an inner supported position, wherein at least two of the side support surfaces (4a, 4b, 4a', 4b') are supported by at least two side contact surfaces (3a, 3b, 3a', 3b'), and an outer indexing position, wherein the at least two side support surfaces (4a, 4b, 4a', 4b') are out of contact with the two side contact surfaces (3a, 3b, 3a', 3b'), - the internal indexing mechanism (6, 6') having a shaft member (7, 7') with a shaft centre axis (C 3, C 3 ') extending inside a bore (8, 8') formed in the tool body (2, 2'), the indexable cutting insert (4, 4') being connected at a first end (7a, 7a') of the shaft member (7, 7') and a second end (7b, 7b') of the shaft member being arranged for pushing the shaft member with the indexable cutting insert (4, 4') to the outer indexing position, wherein the shaft member is forced toward the inner supported position by a compressible force generator, wherein the indexable cutting insert (4, 4') has a multi-sided shape as seen in the direction of the insert centre axis (C 2, C 2 ') and the side support surfaces (4a, 4b, 4a', 4b') are included in the sides of the multi-sided indexable cutting insert (4, 4'), wherein the internal indexing mechanism (6, 6') is arranged to provide a rectilinear movement along the shaft centre axis (C 3, C 3 '), between the inner supported position and the outer indexing position, characterized in that the indexable cutting insert (4, 4') is free to turn in both directions around the insert centre axis (C 2, C 2 ') in the outer indexing position. - a tool body (2, 2') being rotatable around a central rotation axis (C 1, C 1 '), the tool body comprising at least one insert seat (3, 3') with a plurality of side contact surfaces (3a, 3b, 3a', 3b'), - at least one indexable cutting insert (4, 4') including an insert centre axis (C 2, C 2 ') around which the indexable cutting insert (4, 4') has a rotational symmetry, wherein the indexable cutting insert (4, 4') has a plurality of side support surfaces (4a, 4b, 4a', 4b'), which are situated around the insert centre axis (C 2, C 2 ') and arranged to be supported by the side contact surfaces (3a, 3b, 3a', 3b') of the insert seat (3, 3'), - at least one internal indexing mechanism (6, 6') being arranged to displace the indexable cutting insert (4, 4') between an inner supported position, wherein at least two of the side support surfaces (4a, 4b, 4a', 4b') are supported by at least two side contact surfaces (3a, 3b, 3a', 3b'), and an outer indexing position, wherein the at least two side support surfaces (4a, 4b, 4a', 4b') are out of contact with the two side contact surfaces (3a, 3b, 3a', 3b'), - the internal indexing mechanism (6, 6') having a shaft member (7, 7') with a shaft centre axis (C 3, C 3 ') extending inside a bore (8, 8') formed in the tool body (2, 2'), the indexable cutting insert (4, 4') being connected at a first end (7a, 7a') of the shaft member (7, 7') and a second end (7b, 7b') of the shaft member being arranged for pushing the shaft member with the indexable cutting insert (4, 4') to the outer indexing position, wherein the shaft member is forced toward the inner supported position by a compressible force generator,