Single-reel type tape cartridge, and tape drive

A single-reel type tape cartridge comprising:

• a main body case including an upper case and a lower case;
• a tape reel which is housed in the main body case and on which a recording tape is wound;
• and
• a floating-lock structure, which is provided between an upper surface of the tape reel and the upper case, for restricting upward movement of the tape reel in nonuse status, wherein
• an outer surface of the upper case has an entry groove which has a recessed section and which is to be engaged with an unlock member provided in a tape drive so as to guide relative entry of the unlock member, and
• a loading posture of the main body case relative to the tape drive is restricted by engagement between the unlock member and the entry groove and by guidance of the relative entry thereof in a process in which the main body case is loaded into the tape drive, and the floating-lock structure is unlocked by action of the unlock member on the floating-lock structure with the unlock member being engaged with the entry groove.