Post-quantum cryptography (PQC) has gained sub-stantial attention from various communities recently. Along with the ongoing National Institute of Standards and Technology (NIST) PQC standardization process that targets the general-purpose PQC algorithms, the research community is also looking for efficient lightweight PQC schemes. Among this direction of efforts, Ring-Binary-Learning-with-Errors (RBLWE)-based encryption scheme (RBLWE-ENC) is regarded as a promising lightweight PQC fitting Internet-of-Things (IoT) and edge computing applications. As hardware implementation for PQC algorithms has become one of the major advances in the field, in this paper, we follow this trend to present an efficient implementation of RBLWE-ENC lightweight accelerator on the field-programmable gate array (FPGA) platform. Overall, we have demonstrated three coherent interdependent stages of efforts: (i) we have presented detailed derivation processes to formulate the proposed algorithmic operation; (ii) we have then implemented the proposed algorithm into a desired hardware accelerator; and (iii) we provided thorough complexity analysis and comparison to showcase the superior performance of the proposed accelerator over the state-of-the-art designs, e.g., the proposed accelerator with $v=8$ has at least 66.67% less area-time complexities than the existing ones (Virtex-7 FPGA). We hope the outcome of this work can facilitate lightweight PQC development.