  We investigate scalarized charged black holes in the Einstein-Maxwell-Scalar
theory with two U(1) fields inspired by the $N=4$ supergravity. From the onset
of the spontaneous scalarization (tachyonic instability of
Reissner-Nordstr\"{o}m black hole), these black holes are classified by the
number of $n=0,1,2,\cdots$, where $n=0$ is called the fundamental black hole
and $n=1,2,\cdots$ denote the $n$-excited black holes. Adopting radial
perturbations, we show that the $n=0$ black hole is stable against the
$s(l=0)$-mode scalar perturbation, whereas the $n=1,2$ excited black holes are
unstable. This implies that the $n=0$ black hole is considered as an endpoint
of the Reissner-Nordstr\"{o}m black hole.
