Optical measurement cell

An optical measurement cell having a pair of optical windows sandwiching a flow channel accommodating a sample solution, comprising:

• a cell body provided with an accommodating recess having a through hole formed in a part of a bottom surface thereof, and a solution introduction part and a solution deriving part which are communicating with an inner circumferential surface of the accommodating recess;
• a pair of light transmitting members accommodated in the accommodating recess and forming the pair of optical windows;
• a spacer contacting respective opposing surfaces of the pair of light transmitting members and defining a distance between the opposing surfaces;
• and
• a pressing mechanism for pressing the pair of light transmitting members and the spacer toward the bottom surface of the accommodating recess to be brought into close contact with each other so as to form the flow channel connecting to the solution introduction part and the solution deriving part between the pair of light transmitting members,
• wherein a pair of positioning recesses, each having a shape corresponding to the spacer, are provided on at least one opposing surface of the pair of light transmitting members and the spacer is fitted in the positioning recesses so as to be positioned substantially.