The present invention relates to a method for manufacturing a device for holding a light guide, for use in a flow cell, with the steps of providing a light guide holder having a first end and a second end connected by a longitudinal through hole with a narrow portion at the first end having a first diameter and a wide portion at the second end having a second diameter, the first diameter being smaller than the second diameter, and the narrow portion and wide portion being connected by a tapering portion, inserting a light guide into the through hole so that a first end of the light guide extends from the first end to the second end of the light guide holder, inserting a substance into at least part of the wide portion of the through hole, Inserting a tube between the light guide and the light guide holder, and fix the light guide in relation to the holder by means of the substance. The invention also relates to a device for holding a light guide.