A blood vessel characteristics measurement device (100) is provided with a blood flow measurement unit (20) held at a position opposite to a skin surface (10) in a measured region of an examinee, an optical sensor unit (30) built in the blood flow measurement unit (20), an electrocardiographic monitor (40), and a control device (50). The control device (50) has a blood flow measuring means (60), a blood vessel displacement deriving means (70), and a blood vessel condition deriving means (80). The blood flow measuring means (60) measures the displacement of a blood vessel and blood vessel surrounding tissue due to a blood flow in accordance with the intensity of light when light receiving units (34, 36) receive the light projected from a light emitting unit (32) of a sensor unit (30). The blood vessel displacement deriving means (70) derives the displacement of an inner wall of a blood vessel (12) in accordance with a blood vessel and blood vessel surrounding tissue. The blood vessel condition deriving means (80) seeks a pulse transmission speed in each measurement position in accordance with a phase difference between an electrocardiographic signal waveform of the electrocardiographic monitor (40) and a detection signal waveform obtained from the receiving units (34, 36), thereby deriving the displacement condition of the inner wall of the blood vessel (12) from the pulse transmission speed.
