To provide a hard hand-off method where the danger of signal interruption caused by frequently executing hand-off is reduced in a digital mobile communication system.

In a hard hand-off method for a digital mobile communication system, even in the case that a request of hand-off is made depending on the strength of a pilot signal received by a mobile terminal, a guard time period t1 not conducting hard hand-off and a guard level P2 conducting the hard hand- off when the strength of the pilot signal reaches a prescribed level or below, are set.