ABSTRACT In this paper the angle of repose of sands is investigated; the slope angle of conical heaps of granular materials formed statically on a flat plate were observed as a typical angle of repose. The relationship of the angle of repose with the angle of internal friction is explained with regard of the deformation mechanism for the sliding layer of the heap on a thin surface. Some series of tests were conducted on plates with different roughness, and the factors influencing the measurement of the angle of repose were examined, including: the size, material pouring rate and boundary friction effects. In order to aVold the effects of the unfavorable influence factors, a rational method of measurement was proposed and the device for using this method is introduced.