A silicon vertex detector has been developed for the BELLE experiment at the KEK B-factory to be used to determine the relative displacements of B-meson decay vertices for CP violation measurements. The device has been successfully installed and operated with high-luminosity beam conditions. The average strip yield is larger than 96%, including the preamplifier electronics yield and the detector is currently working stably with a signal-to-noise ratio of 17-40. The measured impact parameter resolution agrees with expectations based on Monte Carlo simulations, and the measured D 0 lifetime is in good agreement with the particle data group's average of other measurements. Several B→J/ψK events produced at the ϒ(4S) resonance have been detected and separate decay vertices have been found.