Abstract: The invention relates to a device (10) for truing a machining wheel (20), in particular grinding or eroding wheel, by means of a rotating truing tool (30), comprising: a first rotating spindle (18), which can be driven so as to rotate about a first axis of rotation (22), for attaching the machining wheel (20) and a second rotating spindle (28), which can be driven so as to rotate about a second axis of rotation (32), for attaching the truing tool (30), wherein, in order to true the machining wheel (20), the truing tool (30) rotatably driven by the second rotating spindle (28) can be brought into material-removing contact with the machining wheel (20) rotatably driven by the first rotating spindle (18). In this respect, in order to obtain uniform truing results, the first axis of rotation (22) is directed substantially orthogonally to the second axis of rotation (32) during the entire truing process.