Abstract: An apparatus for track-based detection of the wheel profile (2,3) of passing railway wheels (1) when these are passing a measuring stretch comprises a measuring apparatus (5) with a generator (6) for laser light and a receiver (7) for reflected laser light from a reflection point (8). The measuring apparatus (5) has no movable parts in that the measuring is carried out along a relative to the wheel axle fixed but perhaps skew rectilinear base line (M) which is intersected by the wheel during the passing thereof whereby the wheel profile is scanned along an inclined path. The apparatus moreover measures the sideways position of the wheel on the rail and the travelling speed of the wheel and the deflection of the track (4). All measuring results are processed and compared with the measuring result from a measured reference profile of a perfect wheel whereby, for example, flange height, flange width and maximum deviation between measured value and reference value may be computed.