The present invention relates to a cell for optical analysis, wherein a flow space of a low depth is formed by attachment, using a simple double-sided tape without out special processing, of a microchannel through which a liquid sample passes, thereby enabling: a very easy manufacturing method; a reduction of manufacturing costs, thereby allowing the cell to be more widely used; a maintenance of a short path-length of light with respect to the flow space in which the liquid sample flows, thereby enabling accurate optical analysis without diluting a sample with high absorbance; an expansion of a flow space region along the plane vertical to the light-passing direction, thereby enabling smoother optical analysis and improving the accuracy of optical analysis.