We study flavor-changing bottom quark radiative decay $ b {\rightarrow} s \gamma $ induced at the one-loop level within the minimal gauged two-Higgs-doublet model (G2HDM). Among the three new contributions to this rare process in G2HDM, we find that only the charged Higgs $ {\cal{H}}^\pm $ contribution can be constrained by the current global fit data in $\textit{B}$-physics. The other two contributions from complex vectorial dark matter $ {\cal{W}} $ and dark Higgs $ {\cal{D}} $ are not sensitive to the current data. Incorporating theoretical constraints imposed on the scalar potential and electroweak precision data for the oblique parameters, we exclude mass regions $ m_{\cal{H}}^\pm \lesssim 250 $ GeV and $ m_{\cal{D}} \lesssim 100 $ GeV at the 95% confidence level.