PURPOSE: To provide a filler unit capable of filling a clearance between a wall and the side end of a top board and executing work with a good appearance, when furniture such as a washstand, sink or dressing table, on the top board of which certain manual work is performed, is installed in a space between opposing walls.

CONSTITUTION: An end cap 2 covering at least the side end face and the top of the side end of a top board 1 is mounted in an outwardly movable manner through a flexible material 3 which applies spring force outwardly between the end cap 2 and the side end face of the top board 1 in the side end of the top board 1 of furniture to be installed in a space between opposing walls A, A.