A blood pressure measuring device and measuring method thereof with which the systolic pressure can be precisely measured by oscillo-metric double cuff way. The measuring device comprises a cuff 2, a blood flow occluding air bag 8 for oppressing entire blood pressure measuring spot, a sub-air bag 7 for oppressing the blood pressure measuring spot at the side near the heart, a cuff body 1 formed of a pulse detecting air bag 5 oppressing the lower blood flow side of the blood pressure measuring spot to detect the pulse wave thereof, conduits 11, 12. 13 for compressing and releasing pressure, compressing and releasing means 23 connected via a damper 18 and a valve 16, cuff pressure detecting means 31, 32, 33 for detecting variation of the pressure in the pulse detecting air bag to obtain cuff pressure signals, and a pulse wave detecting means 35 for detecting the pulse wave superposed on the cuff pressure signals to obtain pulse wave signals. Besides, in order to avoid the pulse wave of the vein above the cuff to be detected by the pulse wave detecting means via blood flow occluding air bag so as to perform systolic blood pressure measuring with a preferable S/N ratio, the device is provided with a first conduit connected with a first valve 115-2 between the blood flow occluding air bag and the compressing and releasing means, a second conduit connected with a second valve 115-1 between the sub-air bag and the compressing and releasing means, and a third conduit connecting the pulse wave detecting air bag and the cuff pressure detecting means via a third valve 116, a bypass flow passage formed of a first fluid resistance 14 is provided between the first conduit connected to the blood flow occluding air bag and the third conduit connected to the pulse wave detecting air bag.本發明係關於一種血壓測定裝置，示波儀式的雙拷套方式中，可正確的實施收縮期血壓測定的血壓測定裝置與血壓測定方法，其具備有拷套部材2，壓迫整個血壓測定部位用的阻血用空氣袋8，壓迫血壓測定部位心臟側用的副空氣袋7，由壓迫血壓測定部位血管下流側，且檢出下流側脈波用的脈波檢出用空氣袋5所構成的拷套本體1，加壓及減壓用的配管11、12、13，透過阻尼裝置18及啟閉閥16連接之加減壓機構23，從脈波檢出用
