<p>Disclosed is a recording tape cartridge wherein two communication units having different communication methods can be effectively built into a case. A recording tape cartridge (10) is provided with: a reel (20) whereon recording tape (T) is wound; a case (12) wherein the reel (20) is housed; and a composite communication device (70), which is provided inside the case (12). A memory board unit (70A) in the composite communication device (70) is formed so as to have an antenna (76) and an IC chip (74) provided on a first base section (72A) of a base sheet (72); and a UHF band RFID tag section (70B) is formed so as to have the IC chip (74) provided on the first base section (72A) of the base sheet (72), and a tag antenna (78) provided on a second base section (72B).</p>
