The present invention reduces thermal stress that is generated in a join portion of a window material in an optical measurement cell, and is an optical measurement cell having translucent windows through which light is transmitted and into an interior of which is introduced a test sample. This optical measurement cell has a planar window material that forms the translucent windows, a join supporting portion that is joined to an outer edge portion of a main surface of the window material and supports the window material, and a low thermal expansion component that is provided on an outer-side circumferential surface of the join supporting portion and whose coefficient of thermal expansion is lower than a coefficient of thermal expansion of the join supporting portion.