  The purpose of this paper is to construct a crepant resolution of quotient
singularities by trihedral groups ( finite subgroups of SL(3,C) of certain type
), and prove that each Euler number of the minimal model is equal to the number
of conjugacy classes. Trihedral singularities are 3-dimensional version of
D_n-singularities, and they are non-isolated and many of them are not complete
intersections. The resolution is similar to one of D_n-singularities. There is
a nice combination of the toric resolution and Calabi-Yau resolution.
