We have made high-field magnetization measurements for some Mn alloys : ε-Mn_Ga with δ= -0.30, ε-(Mn_Fe_x)_3Sn with x=0.1 and 0.3, Fe_3Mn_4Ge_ and γ-(Mn_Fe_x)_Ga_y with x=0.44 and y=0.27. The ε-Mn_Ga has the hexagonal D0_ type structure and a distorted triangular antiferromagnetic spin structure. The hexagonal lattice is slightly distorted to an orthorhombic lattice at T_d of about 290 K with large magnetization. Pseudo-binary ε-(Mn_Fe_x)_3Sn has also the D0_ type structure, and the alloys with x has an hp13-type structure, and shows an antiferromagnetism below 470 K. The isothermal magnetization at 77 K shows a steep increase around 110 kOe, suggesting the metamagnetic transition. The γ-(Mn_Fe_x)_Ga_y is face centered cubic. The alloys with x=0.4～0.5 and y=0.27 show coexistence of an antiferromagnetic state and a ferromagnetic state below Neel temperature (T_N～300K), and a typical ferromagnetic behavior above T_N ( Curie temperature T_C>550 K). The magnetization of the coexisting state at 77 K in a field of 150 kOe was comparable to that of the ferromagnetic state at 300 K
