An ink cartridge (40) includes; an ink bag (42); a moving body (62) configured to move relative to the case (41); a single detecting unit (66); and a storing unit (125). The detecting unit (66) is configured to output a signal corresponding to a position of the moving body (62) relative to the case (41). The storing unit stores time length data indicative of a length of time to be taken by a value of the signal outputted from the detecting unit to change from a first prescribed value to a second prescribed value different from the first prescribed value. It is possible to allow a recording head to maintain desirable ejection characteristics even when the ink cartridge is mounted to a recording device at a high speed.