Provided is a sphygmomanometer capable of measuring a blood pressure value even when measuring the blood pressure of a heart transplant patient transplanted with a living heart transplant or an auxiliary artificial heart or a pulse weak person such as a person with weak pulse wave. The sphygmomanometer (1) comprises an armband portion (2) having an air bag for ischemia (14) for compressing the upper arm of the person to be measured and an air bag for pulse wave detection (250) for detecting the pulse wave of the person to be measured. A pressurizing mechanism (110) for pressurizing the inside of the ischemic air bag and the pulse wave detecting air bag, a depressurizing mechanism (111, 112) for depressurizing the inside of the ischemic air bag and the pulse wave detecting air bag, and for ischemia A pressure sensor (140) for detecting the pressure in the air bag and the pressure in the air bag for pulse wave detection, and a control unit (120) for detecting the blood pressure value and the pulse wave by a signal from the pressure sensor, When the subject is a pulse weak person, the unit (120) is used to suppress blood when the maximum amplitude (MM) of the pulse wave is generated when the inside of the air bag for ischemia and the inside of the air bag for pulse wave detection are decompressed. The pressure in the air bladder (14) is determined as the average blood pressure value (PM) of the person being measured.生体心臓移植，補助人工心臓を移植した心臓移植患者あるいは脈波の弱い人のような脈弱者の血圧を測定する場合であっても、血圧値を測定することができる血圧計を提供する。血圧計（１）は、被測定者の上腕を圧迫する阻血用空気袋（１４）と被測定者の脈波を検出する脈波検出用空気袋（２５０）を有する腕帯部（２）と、阻血用空気袋と脈波検出用空気袋内を加圧する加圧機構（１１０）と、阻血用空気袋と脈波検出用空気袋内を減圧する減圧機構（１１１，１１２）と、阻血用空気袋内の圧力と脈波検出用空気袋内の圧力を検出する圧力センサ（１４０）と、圧力センサからの信号により血圧値と脈波の検出をする制御部（１２０）を有し、制御部（１２０）は、被測定者が脈弱者である場合に、阻血用空気袋内と脈波検出用空気袋内を減圧する際に、脈波の最大振幅（ＭＭ）が発生した時の阻血用空気袋（１４）内の圧力を、被測定者の平均血圧値（ＰＭ）として決定する。
