  We investigated the annealing effects on the physical properties of
SrFe$_2$(As$_{1-x}$P$_x$)$_2$ ($x=0.35$). The superconducting transition
temperature ($T_c$) increased from 26 K to 33 K by annealing. The X-ray
diffraction measurement suggested that the annealed crystals have the
shorter/longer $a/c$-axes and the larger pnictogen height $h_\mathrm{Pn}$. This
must be linked to the $T_c$-enhancement by annealing. Moreover, it was found
that the post-annealing decreased the electronic specific heat coefficient at
$T$=0 K, $\gamma_r$, and changed the magnetic field ($H$) dependence from
sub-linear $\gamma_r\propto H^{0.7}$ to $H$-linear $\gamma_r\propto H$. This
can be attributed the electronic change from dirty to clean superconductors
with $s_{\pm}$ gap.
