  Hawking evaporation of primordial black hole (PBH), with mass $3\times
10^{-17} \lesssim M_{\rm PBH}/M_\odot \lesssim 7\times 10^{-17}$ and fractional
abundance $0.01 \lesssim f_{\rm PBH} \lesssim 0.5$, well reproduces 511 keV
gamma-ray excess from galaxy center. In this work, we investigated the
production mechanism of PBHs base on the first-order phase transition induced
by quartic effective thermal potential of a scalar field in dark sector. We
found the phase transition with vacuum energy, $\mathcal{O}(1)\lesssim
B^{1/4}/{\rm MeV} \lesssim \mathcal{O}(100)$, produces the desired PBH mass and
abundance fraction. Correlated signatures of gravitational wave and
extragalactic gamma-ray from phase transition and black hole evaporation,
respectively, are within $\mu$Ares and AMEGO/e-ASTROGAM projected
sensitivities.
