Abstract: A culture sample holder, which can be placed in a culture apparatus comprises an inner holder, which is hollow inside, and an outer holder, which is hollow inside. The inner holder is insertable in the outer holder to an assembly of the inner holder and outer holder where the outer bottom of the inner holder faces the inner bottom of the outer holder, thus forming a space for a culture sample to be placed between the outer bottom and the inner bottom. The inner holder comprises a protrusion and the outer holder comprises a recess in its side wall. The protrusion is placed in a first position of the inner holder inside said recess in the side wall of the outer holder and in a second rotated position of the inner holder, the protrusion is placed in the outer holder outside the recess at a higher position with respect to the first position.