Medium energy (40--65 MeV) \ensuremath{\gamma} rays following radiative capture of 50 MeV polarized protons on $^{11}\mathrm{B}$ were studied for the first time by using a NaI detector ensemble with good energy resolution and small background counts. Discrete \ensuremath{\gamma} rays feeding the ground ${0}^{+}$, 4.44 MeV ${2}^{+}$, and 9.64 MeV ${3}^{\mathrm{\ensuremath{-}}}$ states, and prominent \ensuremath{\gamma} peaks feeding the 19 and 22 MeV excitations region in $^{12}\mathrm{C}$ were identified. The analyzing powers of the radiative capture were found to depend on the microscopic configurations of the final states.