  We search for CP violation in the decay $D^+\rightarrow K^0_S K^+$ using a
data sample with an integrated luminosity of 977 fb$^{-1}$ collected with the
Belle detector at the KEKB $e^+e^-$ asymmetric-energy collider. No CP violation
has been observed and the CP asymmetry in $D^+\rightarrow K^0_S K^+$ decay is
measured to be $(-0.25\pm0.28\pm0.14)%$, which is the most sensitive
measurement to date. After subtracting CP violation due to $K^0-\bar{K}^0$
mixing, the CP asymmetry in $D^+\rightarrow\bar{K}^0 K^+$ decay is found to be
$(+0.08\pm0.28\pm0.14)%$.
