Disclosed in various embodiments of the present invention are: an apparatus using a modulation and coding scheme (MCS) index table in a wireless communication system; an MCS index table determination method therefor; and an apparatus therefor. According to various embodiments of the present invention, an electronic device comprises at least one communication circuit for supporting wireless communication with a base station, a memory for storing at least two MCS index tables, and a processor operatively connected to the communication circuit and the memory, wherein the processor receives downlink control information (DCI), which includes a retransmission MCS index so as to be retransmitted from the base station, by using the communication circuit when a cyclic redundancy check (CRC) fails, compares same with the retransmission MCS index stored in the memory, on the basis of the retransmission MCS index of the downlink control information, determines a mismatch between the MCS index tables on the basis of determining that the retransmission MCX indexes differ, and restores the MCS index table on the basis of determining the mismatch between the MCS index tables. Additional various embodiments are possible.