  Let $P$ be a partially ordered set, $R$ a commutative unital ring and
$FI(P,R)$ the finitary incidence algebra of $P$ over $R$. We prove that each
$R$-linear higher derivation of $FI(P,R)$ decomposes into the product of an
inner higher derivation of $FI(P,R)$ and the higher derivation of $FI(P,R)$
induced by a higher transitive map on the set of segments of $P$.
