  Given a space $X$ and a simplicial complex $K$ with $m$-vertices, the
arrangement of partially diagonal subspaces of $X^m$, called the dragonal
arrangement, is defined. We decompose the suspension of the diagonal
arrangement when $2(dim K + 1) < m$, which generalizes the result of Labassi.
As a corollary, we calculate the Euler characteristic of the complement when
$X$ is a closed connected manifold.
