For data packet transmission in special format generated by connecting or patching data frames, a request packet and reply packet receivable only by STAs supporting the special format are transmitted/received before the data packet transmission, to check and manage the STA supporting the special format. Based on management information in own station, the data packet is transmitted in the special or standard format according to a receive-side STA. For generating plural data packets in special format in which plural data frames are patched, the plural data frames having subheaders added are connected and divided to data blocks. A main header including information necessary to restore patched data frames are added to each data block, and a control information field and a frame check field of a data packet are added before and after the data block having the main header added thereto, respectively, to generate data packets.