Magnetization and demagnetization behaviors of ordered &bgr;′‐NiAl B2 phase are measured as a function of time under the constant applied fields by varying the electronic circuit time constant &tgr;cof magnetometer. It is clarified that the &bgr;′‐NiAl does not have magnetic after effect at room temperature. The after effect of the phase observed previously at &tgr;c=30 sec was found to be the circuit response of the measurement system. This response showed the Voigt‐Kelvin type anelastic behavior.