A shaving unit for use in a shaving device, said shaving unit comprising a supporting member (19, 21a, 21b, 21c) and at least two hair cutting units (7a, 7b, 7c) supported by the supporting member, wherein each hair cutting unit comprises: - an external cutting member with hair-entry openings; and - an internal cutting member which is rotatable relative to the external cutting member about an axis of rotation and which has a plurality of hair-cutting elements; wherein the shaving unit further comprises a retaining structure (23a, 23b, 23c) which is releasably couplable to the supporting member and which is configured to retain the at least two hair cutting units in an operational position relative to the supporting member in an assembled condition of the shaving unit; and wherein the retaining structure comprises, for each respective hair cutting unit of the at least two hair cutting units, a locking member comprising at least one locking element (79a, 79b) which, in the assembled condition of the shaving unit, is biased by spring force towards the external cutting member of the respective hair cutting unit and engaged by an engagement element (87a, 87b) of the external cutting member to prevent rotation of the external cutting member about the axis of rotation, characterized in that the retaining structure comprises, for each respective hair cutting unit (7a, 7b, 7c) of the at least two hair cutting units, a separate retaining member (23a, 23b, 23c) which is releasably couplable to the supporting member (19, 21a, 21b, 21c) and which is configured to separately retain the respective hair cutting unit in an operational position relative to the supporting member independently from any other of the at least two hair cutting units; wherein the locking member provided for the respective hair cutting unit is separately arranged from any other locking member, provided for any other of the at least two hair cutting units, and integrated with the separate retaining member provided for the respective hair cutting unit. - an external cutting member with hair-entry openings; and - an internal cutting member which is rotatable relative to the external cutting member about an axis of rotation and which has a plurality of hair-cutting elements; wherein the shaving unit further comprises a retaining structure (23a, 23b, 23c) which is releasably couplable to the supporting member and which is configured to retain the at least two hair cutting units in an operational position relative to the supporting member in an assembled condition of the shaving unit; and wherein the retaining structure comprises, for each respective hair cutting unit of the at least two hair cutting units, a locking member comprising at least one locking element (79a, 79b) which, in the assembled condition of the shaving unit, is biased by spring force towards the external cutting member of the respective hair cutting unit and engaged by an engagement element (87a, 87b) of the external cutting member to prevent rotation of the external cutting member about the axis of rotation, characterized in that the retaining structure comprises, for each respective hair cutting unit (7a, 7b, 7c) of the at least two hair cutting units, a separate retaining member (23a, 23b, 23c) which is releasably couplable to the supporting member (19, 21a, 21b, 21c) and which is configured to separately retain the respective hair cutting unit in an operational position relative to the supporting member independently from any other of the at least two hair cutting units; wherein the locking member provided for the respective hair cutting unit is separately arranged from any other locking member, provided for any other of the at least two hair cutting units, and integrated with the separate retaining member provided for the respective hair cutting unit.