AbstractHere we want to investigate X-shaped radio galaxy 3C 315, which is a FRII source, but it lies very close to the FRI/FRII borderline. We used publicly available data from Leahy’s atlas of double radio-sources and NASA/IPAC Extragalactic Database (NED) in order to investigate its flux density, as well as the spectral index distribution. We obtained spectral index distributions between the frequencies: 1417 MHz - 2695 MHz and 1646 MHz - 2695 MHz. Our conclusion is that the synchrotron radiation is the dominant radiation mechanism over most of the area of 3C 315. Because of very poor hotspots (i.e. warmspots) we investigated which part of the source represents more active regions. The results of this study would be helpful to understand the evolutionary process of the galaxy 3C 315. - FULL TEXT available in PDF.