The manganese concentration x dependence of the average magnetic moment μo, the Curie temperature Tc, the pressure effect on Tc and the electric resistance for the ferromagnetic amorphous alloys (Co_ Mn_x)B were investigated. The Curie temperature decreases linearly with increasing x and μo had a maximum around x=0.15. The magnetic susceptibility vs. temperature curves for all the prepared amorphous alloys obey the Curie-Weiss law above Tc. The pressure effect on Tc is that Tc has a value of 1.06 K/kbar at x=0 and is decreasing with increasing x and becomes zero at x=0.4. These results are analyzed on the basis of the pair interaction model and the local enviroment effect. There arise two kinds of minimum in the resistance vs. temperature curves. That the resistance minimum at high temperature has a strong correlation with Tc is assured by measuring the transverse effect of the resistance with amorphous alloys x=0.4. The resistance minimum for the amorphous alloys and crystalline compounds are found at low temperature under ferromagnetic state
