This paper describes a highly sensitive optical fibre interferometric vibration sensing system. The system is capable of measuring three dimensionally high frequency mechanical vibration amplitudes down to the order of 0.1-0.01 Å at frequencies ranging from 10 kHz up to 30 MHz. The system is stabilized by a unique feedback compensation scheme against phase variations appearing in two interfering light beams due to various disturbances. Use of this scheme has hence realized highly sensitive semiautomatic scanning measurements.