The crystal structure of babingtonite was determined from neutron diffraction data at 80K. The lattice constants are a=7.497(1), b=12.225(1), c=6.710(1) Å, α=86.18(1), β=93.90(1) and γ=112.27(1)° (at room temperature). The structure was refined assuming the space group symmetry of P-1. The cation distributions of Mn and Mg in Fe(1) site and Al in Fe(2) site were confirmed by applying the differences of the scattering lengths of the atoms in neutron diffraction. The accurate positions of the hydrogen atoms were determined.