A heterodyne laser Doppler probe, comprising: (a) a first optical path for guiding excitation light; (b) a second optical path for guiding measurement light; and (c) an optical probe body including a reflection mirror, a 1/4 wavelength plate arranged in the second optical path, a beam splitter, and a focal lens, wherein, in use: the excitation light from the first optical path is received by the reflection mirror, said excitation light from the reflection mirror is reflected by the beam splitter and introduced through the focal lens on to a measurement object; and the measurement light from the second optical path passes through the 1/4 wavelength plate to be converted from linearly polarized light into circularly polarized light, said measurement light from the 1/4 wavelength plate is transmitted by the beam splitter and introduced into the focal lens on to the measurement object, reflected off the measurement object through the focal lens and transmitted by the beam splitter to thereby introduce said reflected measurement light into the 1/4 wavelength plate to be converted from circularly polarized light into linearly polarized light, and then returned through the second optical path to a heterodyne laser Doppler measurement device. (a) a first optical path for guiding excitation light; (b) a second optical path for guiding measurement light; and (c) an optical probe body including a reflection mirror, a 1/4 wavelength plate arranged in the second optical path, a beam splitter, and a focal lens, wherein, in use: the excitation light from the first optical path is received by the reflection mirror, said excitation light from the reflection mirror is reflected by the beam splitter and introduced through the focal lens on to a measurement object; and the measurement light from the second optical path passes through the 1/4 wavelength plate to be converted from linearly polarized light into circularly polarized light, said measurement light from the 1/4 wavelength plate is transmitted by the beam splitter and introduced into the focal lens on to the measurement object, reflected off the measurement object through the focal lens and transmitted by the beam splitter to thereby introduce said reflected measurement light into the 1/4 wavelength plate to be converted from circularly polarized light into linearly polarized light, and then returned through the second optical path to a heterodyne laser Doppler measurement device. the excitation light from the first optical path is received by the reflection mirror, said excitation light from the reflection mirror is reflected by the beam splitter and introduced through the focal lens on to a measurement object; and the measurement light from the second optical path passes through the 1/4 wavelength plate to be converted from linearly polarized light into circularly polarized light, said measurement light from the 1/4 wavelength plate is transmitted by the beam splitter and introduced into the focal lens on to the measurement object, reflected off the measurement object through the focal lens and transmitted by the beam splitter to thereby introduce said reflected measurement light into the 1/4 wavelength plate to be converted from circularly polarized light into linearly polarized light, and then returned through the second optical path to a heterodyne laser Doppler measurement device.