The first experiment of a new impedance probe, called the gyroplasma probe, was carried out by using K-9M-13 rocket launched at 1210 JST, on July 27, 1965 from KSC (Kagoshima Space Center), Japan. Two spheres with radius 20mm are sticked out into the ionospheric medium and sustained by the thin and short booms symmetrically for the rocket body. Impedance of this probe system is measured in the frequency range from 0. 5 Me to 16 Me, swept continuously in 0. 93 second. The date was obtained from 80km to 317km, successfully. Theoretical result on the performance of the RF impedance probe in wide frequency range was confirmed by detecting the upper hybrid resonance and so called sheath resonance in each sweep interval. The accurate electron density was deduced from the upper hybrid resonance frequency 〓, where fp is plasma frequency and fa is the electron gyro-frequency. An detailed structure of the ionosphere under the stormy condition which is characterised by the existence of a valley structure between F_1 and F_2 layers was disclosed. The second experiment was performed by using K-9M-14 rocket launched at 1200 JST, on October 4, 1965 from KSC. To ascertain the resonance effects observed in the first experiment, two fixed frequencies, 1.15 Me and 5.01 Me were employed for measurement of the impedance of a short cylindrical-type probe with length 1.20 rn. The detection of three resonances was successful at each height where the employing frequencies correspond to the gyro, sheath and upper-hybrid resonances.