A tape cartridge includes a case, which is made of a lower case and an upper case, for accommodating a reel wound with a magnetic tape. The lower case includes a bottom surface disposed with two positioning holes formed separately from each other on a straight line orthogonal to a direction in which the tape cartridge is loaded into a drive device. The lower case also includes a front wall disposed with two surfaces for regulating a depth to which the case is loaded in the drive device. The two surfaces are positioned on straight lines that pass along the loading direction through the center of the positioning holes when seen from below. Positioning pins of the drive device are inserted into the positioning holes when regulating protrusions of the drive device abut against the two surfaces to regulate the depth to which the case is loaded.