A sidelink data transmission method for ultra-low latency and high reliability communication in a wireless communication system and an apparatus therefor are provided. A method for transmitting sidelink configuration information by a base station according to an embodiment of the present disclosure includes transmitting first sidelink configuration information to a transmitting UE and a receiving UE, transmitting second sidelink configuration information to the transmitting UE and the receiving UE, receiving a result of repeated transmission of sidelink data from the transmitting UE or the receiving UE, determining at least one of whether the sidelink data is retransmitted or the number of repeated transmissions for next sidelink data to be transmitted, and transmitting downlink control information to the transmitting UE and the receiving UE.