About 90% of Sn atoms in β-Mn structure are found by means of neutron diffraction to occupy site II and neither antiferromagnetic long range order nor remarkable short range order was observable. By Mossbauer spectroscopy of 119mSn, the magnitude of the electric field gradient (EFG) decreases with an increase in Sn concentration. The EFG distribution functions are expressed by the sum of two Lorentz distributions. From the stable distribution analysis of internal field distributions, it becomes clear that the magnetic moments randomly freeze in the noncollinear manner. © 1994, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.