An interference observation apparatus for acquiring an interference image of an observation object causes light reflected by or transmitted through the observation object and reference light to interfere with each other using an optical system of a Michelson interferometer or a Mach-Zehnder interferometer, so that the interference image of the observation object can be acquired. The interference observation apparatus disclosed in Non Patent Document 1 uses an optical system of the Mach-Zehnder interferometer, and splits light output from a light source into first split light and second split light, transmits the first split light on the observation object, and combines the first split light and the second split light to acquire an image of interference light generated by the combining.