The invention relates to a rolling element bearing, especially a roller/needle bearing comprising a cage having at least one inner cage and at least one outer supporting cage that comprise windows (3) adapted to the rolling elements (8), with edges (4) connecting a plurality of windows (3), and cross struts, in which the rolling elements (8) are guided and secured from falling out. According to the invention, either the inner cage and the supporting cage are embodied as a slotted inner cage ring and/or a slotted supporting cage ring that can be fixed to each other on the ends, or the inner cage and the supporting cage are embodied as inner cage shells and/or supporting cage shells that can be fixed to each other on the ends.