PURPOSE: To enable the simple arrangement of an insert composed of an assembly of rodlike members by individually inserting the flat rodlike members from an opening of the container thereinto, fixing the rodlike members in place in the receptacle with supports installed in the container and detachably assembling the rodlike members.

CONSTITUTION: Flat rodlike members 4 having a prescribed length, a prescribed thickness and a prescribed width are individually inserted into a receptacle 1 and supported in place in the receptacle 1 with supporting means 11 installed in the receptacle 1 to thereby detachably assemble the rodlike members 4. Thereby, an insert 3 composed of the rodlike members 4 is contrived in the receptacle 1 having an opening 6 in the wall.