We have performed magnetotransport and high-resolution angle-resolved photoelectron spectroscopy (ARPES) measurements on topological insulator ${\mathrm{Pd}}_{x}{\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}(0\ensuremath{\le}x\ensuremath{\le}0.20)$ single crystals. We have observed unusually high values of magnetoresistance ($\ensuremath{\sim}1500%$) and mobility $(\ensuremath{\sim}93\phantom{\rule{0.16em}{0ex}}000\phantom{\rule{0.28em}{0ex}}\mathrm{c}{\mathrm{m}}^{2}\phantom{\rule{0.28em}{0ex}}{\mathrm{V}}^{--1}\phantom{\rule{0.28em}{0ex}}{\mathrm{s}}^{--1})$ at low temperatures for pristine ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$ that decrease upon Pd doping. Shubnikov--de Haas (SdH) oscillations were detected for $x=0.05$, 0.10, confirming the presence of two-dimensional topological surface states (TSSs) for these samples. Hall measurement shows the crossover from $n$-type charge carriers in pristine ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$ to $p$-type charge carriers upon Pd doping. The ARPES measurements show that the conduction band crosses the Fermi level for pristine ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$, and the Dirac point of the TSSs and bulk-derived valence bands indicated a shift to lower binding energy upon Pd doping in a rigid-band-like way up to $x\ensuremath{\sim}0.10$. Based on the comparison of the parameters obtained from the SdH and ARPES measurements, the reduction in the ${k}_{\mathrm{F}}$ value in the magnetotransport measurements is likely due to the band bending induced by the Schottky barrier.