This paper presents a design and performance tests of in-plane gimbal-structured Z-axis gyroscope. The device is manufactured by conventional surface micro machining process using 15µm-thickness epitaxially grown polysilicon. The total size of the device is 4.8mm x 4.8mm in area including 1mm x 1mm core gyro structure and pads for wire bonding. It is designed as two-gimbaled structure which separates inner and outer gimbals. This leads two nearly identical modes of gyroscope, i.e. driving and sensing mode, to mechanically decoupled ones, resulting in enhanced performance. Experiments are accomplished through frequency analysis and dynamic tests using a detection circuit, a vacuum chamber and a rate table. Through experiments, it is confirmed that the designed gyroscope has 0.003 deg/sec resolution, 0.00095 deg/sec/ Hz noise equivalent density, 0.57 % FSO nonlinearity error and 0.02 deg/sec bias stability.