  The spin-dependent inertial force in an accelerating system under the
presence of electromagnetic fields is derived from the generally covariant
Dirac equation. Spin currents are evaluated by the force up to the lowest order
of the spin-orbit coupling in both ballistic and diffusive regimes. We give an
interpretation of the inertial effect of linear acceleration on an electron as
an effective electric field and show that mechanical vibration in a high
frequency resonator can create a spin current via the spin-orbit interaction
augmented by the linear acceleration.
