Based on analyses of previous experimental methods and results, the cross sections of the 186W(n, )187W reaction were measured in the neutron energy range from 0.50 to 1.50 MeV by the activation technique. Neutrons were produced through the T(p,n)3He reaction, and the cross sections of the 197Au(n, )198Au reaction were used to determine the absolute neutron flux. Experimental results agreed with the previous time-of-flight measurements but did not agree with the previous activation measurements. Without the tungsten resonance absorption foils, the measured cross sections of the 186W(n, )187W reaction by the activation method were shown to be larger than the corrected ones because of the interference of the low-energy neutrons.