Double-row roller bearing unit for supporting movable, rotating components of a medical pump, preferably a syringe pump, having a bearing core which forms a first inner bearing surface, partially facing in an axial direction, for first rolling elements and a second inner bearing surface, partially arranged opposite the first inner bearing surface in the axial direction, for second rolling elements; a bearing sleeve which can be attached to a housing portion and forms a first outer bearing surface, opposite the first inner bearing surface, for the first rolling elements; and a bearing pan forming a second outer bearing surface, opposite the second inner bearing surface, for the second rolling elements; and at least one pre-loading element which couples the bearing pan to the bearing sleeve with a defined pre-load in order to form the handleably preassembled double-row roller bearing unit, wherein the pre-loading element is an elastic portion of the bearing pan or of the bearing sleeve which correspondingly at least partially embraces or engages the bearing sleeve or respectively the bearing pan, characterized in that the at least one pre-loading element comprises one or more hold-down devices configured to rest against the housing portion radially outwards in order to press the at least one pre-loading element into an associated engagement contour when the double-row roller bearing unit is installed in the housing portion, and support elements projecting radially outwards are provided, which are provided for support at the housing portion in a second axial load direction and which are elastic in order to be able to deflect radially inwards. a bearing core which forms a first inner bearing surface, partially facing in an axial direction, for first rolling elements and a second inner bearing surface, partially arranged opposite the first inner bearing surface in the axial direction, for second rolling elements; a bearing sleeve which can be attached to a housing portion and forms a first outer bearing surface, opposite the first inner bearing surface, for the first rolling elements; and a bearing pan forming a second outer bearing surface, opposite the second inner bearing surface, for the second rolling elements; and at least one pre-loading element which couples the bearing pan to the bearing sleeve with a defined pre-load in order to form the handleably preassembled double-row roller bearing unit, wherein the pre-loading element is an elastic portion of the bearing pan or of the bearing sleeve which correspondingly at least partially embraces or engages the bearing sleeve or respectively the bearing pan, characterized in that the at least one pre-loading element comprises one or more hold-down devices configured to rest against the housing portion radially outwards in order to press the at least one pre-loading element into an associated engagement contour when the double-row roller bearing unit is installed in the housing portion, and support elements projecting radially outwards are provided, which are provided for support at the housing portion in a second axial load direction and which are elastic in order to be able to deflect radially inwards.