The internal friction Q^ of nickel annealed at 1000℃ for 10hr was measured in a magnetic field by the electrostatic driving method. The results obtained are as follows : (1) With decreasing magnetic field H from a magnetically saturated state, Q^ increases from about H=30 Oe and shows a maximum at H=15 Oe. (2) The magnetic hysteresis loss Q^_h was separated from the whole Q^ through measurement of the dynamic stress with an interference comparameter. (3) When Q^_h is expressed as a function of magentization I/I_s, Q^_h shows a maximum at I/I_s=0.6 ; it becomes smaller with increasing driving frequency f and vanishes at f=5.8 kHz
