PROBLEM TO BE SOLVED: To provide a speculum plate capable of stably measuring a liquid sample.SOLUTION: A speculum plate 1 comprises: a slide glass part 21 including a part regulating a bottom face B1 of a storage part R; a cover glass part 11 arranged oppositely to the slide glass part 21 and including a part regulating a top face U1 of the storage part R; a support part 27 located at least at a part of the circumference of the storage part R and maintaining a state in which the slide glass part 21 is arranged oppositely to the cover glass part 11; a window part for supplying a liquid sample to the storage part R; and a spacer part 15 located at the inside of the storage part R and suppressing shortening of a distance between the slide glass part 21 of the part regulating the bottom face B1 and the cover glass part 11 of the part regulating the top face U1 through elastic bending deformation of at least one of the slide glass part 21 and the cover glass part 11.
