  The magnetic structure of antiferromagnetic $\alpha$-Mn has been unclarified
for almost 70 years since its magnetism was discovered. We measured the
zero-field nuclear magnetic resonance spectra of antiferromagnetic $\alpha$-Mn
to obtain further insight into magnetism below $T_{\text{N}} = 95$ K. The site
II spectra split into two sites with five subpeaks owing to quadrupole
interaction, and this shows that the ordered moments at site II are slightly
tilted from the $[001]$ direction. The site III spectra revealed that this site
splits into four sites below $T_{\text{N}}$. These findings clearly demonstrate
that the antiferromagnetic $\alpha$-Mn symmetry is lower than previously
considered.
