  In this letter, we study collider phenomenology in the supersymmetric
Standard Model with a certain type of non-universal gaugino masses at the gauge
coupling unification scale, motivated by the little hierarchy problem. In this
scenario, especially the wino mass is relatively large compared to the gluino
mass at the unification scale, and the heavy wino can relax the fine-tuning of
the higgsino mass parameter, so-called $\mu$-parameter. Besides, it will
enhance the lightest Higgs boson mass due to the relatively large left-right
mixing of top squarks through the renormalization group (RG) effect. Then $125$
GeV Higgs boson could be accomplished, even if the top squarks are lighter than
$1$ TeV and the $\mu$ parameter is within a few hundreds GeV. The right-handed
top squark tends to be lighter than the other sfermions due to the RG runnings,
then we focus on the top squark search at the LHC. Since the top squark is
almost right-handed and the higgsinos are nearly degenerate, $2b + E_T^{\rm
miss}$ channel is the most sensitive to this scenario. We figure out current
and expected experimental bounds on the lightest top squark mass and model
parameters at the gauge coupling unification scale.
