A method for simultaneously transmitting packets having different lengths to two or more users in a wireless communication system includes: generating the packets to transmit to the respective users, the packets containing information on the maximum transmission length of the packets having different lengths; and simultaneously transmitting the generated packets to the respective users. The maximum transmission length is represented by the number of symbols, and each of the packets sequentially contains control information required for transmitting the packet, data, a tail field, and a PHY pad field, and is generated by inserting a MAC pad between the control information and the data such that the tail field and the PHY pad field are positioned at the last byte of the last symbol of the maximum transmission length.