In order to supply a method and a device that can evaluate the fluidity (viscosity) of blood with good sensitivity in a simple manner, there is provided a blood fluidity evaluation method in which a pressure member is pressed against a test site upon a test subject e.g.a fingertip, blood at the test site is squeezed to flow out to the periphery of the test site, change over time of the amount of blood at the test site is measured at this time using optical scattering, and blood fluidity at the test site is evaluated from this measurement data and, desirably, before the above method, a positioning process is performed in which: the pressure member is pressed against the test site with a weak force pulse measurement data is acquired due to the absorption of light and a relative position, at which the intensity of the pulse measurement data attains a local maximum, is determined as being an optimum measurement position. Pulse measurement data measured at a different site can be used to improve calculation accuracy.
