Abstract: Sudden increases of the ionospheric total electron content (TEC) during the great solar flare burst near 2356 UTon 24 April 1984 were simultaneously observed at Xin-xiang (35.3°N, 113.9°E) and Chongqing(29.5°N, 106.4°E) by means of Faraday rotation measurements of the VHFsignals from the Japanese geostationary satellite ETS-II. These sudden increases lasted three and a half minutes, and the values of TECincreases at Xinxiang and Chongqing reached 9.4×10¹⁶ and 14.3×10¹⁶ ele./m² respectively. The phenomenon recorded by polarimeters is compared with results from neighbouring ionosondes and VLF phase-locked receiver. The analysis shows that there are appreciable increases of electron density both in the ionospheric D-region and the F-region and the latter is the main part of the sharp TEC increases.