A cartridge or a sealing member is provided to reduce the likelihood that a fluid is leaked outside. The cartridge is configured to supply a fluid to a fluid ejection apparatus. The cartridge has: a fluid accommodation portion; and a fluid supply port connectable with the fluid ejection apparatus. The fluid supply port includes: a fluid exit provided to flow out the fluid to the fluid ejection apparatus; and an opening arranged to connect outside of the fluid supply port with inside of the fluid supply port. The opening is not in contact with a side face of the fluid supply port.
