  We explore the feasibility of fault-tolerant quantum computation using the
bit-flip repetition code in a biased noise channel where only the bit-flip
error can occur. While several logic gates can potentially produce phase-flip
errors even in such a channel, we propose bias-preserving implementation of
$S$, $H$, $\mathrm{CZ}$, and $R_z$ gates. We demonstrate that our scheme
improves the computational precision in several tasks such as the time
evolution of quantum systems and variational quantum eigensolver.
