We report the electric transport study of the three-dimensional topological insulator TlBiSe\(_2\). We applied a newly developed analysis procedure and precisely determined two-carrier transport properties. Magnetotransport properties revealed a multicarrier conduction of high- and low-mobility electrons in the bulk, which was in qualitative agreement with angle-resolved photoemission results~[K. Kuroda \(et~al.\), Phys. Rev. Lett. \(\bm{105}\), 146801 (2010)]. The temperature dependence of the Hall mobility was explained well with the conventional Bloch-Gr{\"u}neisen formula and yielded the Debye temperature \(\varTheta_{\rm{D}}=113 \pm 14\)~K. The results indicate that the scattering of bulk electrons is dominated by acoustic phonons.