  In this paper, we present the spectroscopy of 6P$_{1/2}$ state in $^{87}$Rb
using double resonance technique at $780~\text{nm}$ and $421~\text{nm}$. The
double resonance technique is implemented using electromagnetically induced
transparency (EIT) and optical pumping methods. Using these spectroscopy
methods, we have measured the hyperfine splitting of 6P$_{1/2}$ state with
precision of $<$400~kHz which agrees well with other spectroscopy methods such
as electrical discharge and saturated absorption spectroscopy at
$421~\text{nm}$.
