An inkjet printer including a main body device that performs printing by discharging ink from a plurality of inkjet heads (110C, 110M, 110Y, 110K), and ink cartridges (150C, 150M, 150Y, 150K) detachably mounted on the main body device, the inkjet printer being characterized by comprising: a maintenance unit (105, 106) configured to simultaneously perform a maintenance operation on the plurality of inkjet heads; a storage unit (153C, 153M, 153Y, 153K) configured to store, for each type of ink discharged from the plurality of inkjet heads, a manufacturing date or a start-of-use date of the ink cartridge, a normal consumption period from the manufacturing date or the start-of-use date of the ink cartridge to a recommended time limit before the expiration date, cycle and strength of a maintenance operation performed by the maintenance unit before the recommended time limit, and cycle and strength of the maintenance operation performed by the maintenance unit after the recommended time limit; a determination unit configured to determine whether or not the recommended time limit of the ink cartridge has passed, based on the manufacturing date or the start-of-use date and the normal consumption period stored in the storage unit, and an elapsed period from the manufacturing date or the start-of-use date of the ink cartridge; a maintenance setting value decision unit configured to select and decide, in a case where the determination unit determines that the recommended time limit has passed, the shortest cycle and the strongest strength as maintenance setting values for the maintenance unit configured to simultaneously perform the maintenance operation on the plurality of inkjet heads, from among (i) the cycle and the strength of the maintenance operation performed by the maintenance unit before the recommended time limit stored in the storage unit corresponding to the ink cartridge whose recommended time limit is determined to have not passed by the determination unit, and (ii) the cycle and the strength of the maintenance operation performed by the maintenance unit after the recommended time limit stored in the storage unit corresponding to the ink cartridge whose recommended time limit is determined to have passed by the determination unit; and a controller configured to cause the maintenance unit to execute the maintenance operation, based on the maintenance setting values decided by the maintenance setting value decision unit. a maintenance unit (105, 106) configured to simultaneously perform a maintenance operation on the plurality of inkjet heads; a storage unit (153C, 153M, 153Y, 153K) configured to store, for each type of ink discharged from the plurality of inkjet heads, a manufacturing date or a start-of-use date of the ink cartridge, a normal consumption period from the manufacturing date or the start-of-use date of the ink cartridge to a recommended time limit before the expiration date, cycle and strength of a maintenance operation performed by the maintenance unit before the recommended time limit, and cycle and strength of the maintenance operation performed by the maintenance unit after the recommended time limit; a determination unit configured to determine whether or not the recommended time limit of the ink cartridge has passed, based on the manufacturing date or the start-of-use date and the normal consumption period stored in the storage unit, and an elapsed period from the manufacturing date or the start-of-use date of the ink cartridge; a maintenance setting value decision unit configured to select and decide, in a case where the determination unit determines that the recommended time limit has passed, the shortest cycle and the strongest strength as maintenance setting values for the maintenance unit configured to simultaneously perform the maintenance operation on the plurality of inkjet heads, from among (i) the cycle and the strength of the maintenance operation performed by the maintenance unit before the recommended time limit stored in the storage unit corresponding to the ink cartridge whose recommended time limit is determined to have not passed by the determination unit, and (ii) the cycle and the strength of the maintenance operation performed by the maintenance unit after the recommended time limit stored in the storage unit corresponding to the ink cartridge whose recommended time limit is determined to have passed by the determination unit; and a controller configured to cause the maintenance unit to execute the maintenance operation, based on the maintenance setting values decided by the maintenance setting value decision unit.