Measurements of leptonic and semileptonic $B$ meson decays are vital for the determination of CKM matrix elements |$V_{cb}$| and |$V_{ub}$|. This article presents the measurements of semileptonic $B$ decays $B^{0}$ → $D^{∗}\ellν_{\ell}$, $B → D^{(∗)}π\ellν$, $B → η^{ (')}\ellν_{\ell}$ and the leptonic decay $B → μ^{-}ν̄_{μ}$. These analyses use entire Belle data set collected at the $\Upsilon(4S)$ resonance containing 772 million $B\bar{B}$ meson pairs.