An immersion liquid holder 2 is an immersion liquid holder that is used for an observation device 10 for observing sample S by using an immersion method, and includes a supporting member 2b configured to support an absorption member 3 that has absorbed an immersion liquid and a connection unit 2c configured to relatively fix the absorption member 3 that has absorbed the immersion liquid with respect to an optical system, which is an optical system included in the observation device 10, and to fix the absorption member 3 on an optical path of the optical system 1, by fixing the supporting member 2b to the observation device 10.