  Let $M$ be a simply-connected $m$ dimensional manifold of finite type and $k$
a positif integer. In this paper we show that the rational Betti numbers of
each component of the space of immersions of $M$ in $\mathbb{R}^{m+k}$, have
polynomial growth. As consequence, we deduce that, if $M$ is a manifold with
Euler characteristic $\chi\left(M\right)\leq -2$, the Betti numbers of smooth
embeddings, $Emb\left(M ,\mathbb{R}^{m+k}\right)$, have exponential growth if
$k\geq m+1$. The main tool of this work is the construction of an explicit
model of the space of immersions.
