Abstract: A flat cross-shaped test piece is made of sheet metal for biaxially testing of its material. This test piece includes a central region that defines an area of measurement. Four arms for applying loads to the central region extend from the central region along orthogonal axes. Each arm has one end integral with the central region and an opposite end with an end part for connection to a test device for the application of a test load. Tensile stresses can thus be applied to the central region along first and second orthogonal coordinate axes of the central measurement region. Slots in the load applying arms extend along the arms parallel to the first and second coordinate axes from the end part as far as and up to the area of measurement. The slots in the load applying arms prevent the escape of stress trajectories along the arms, thus making it possible to obtain a homogenous stressed state in the central measurement region.