Drawing material container cartridge and drawing material container set

A drawing material container cartridge comprising:

• a cartridge body including a tubular portion that accommodates a drawing material, and being configured to be detachably mounted in a container body by being inserted into the container body along an axial direction that is a direction in which an axis of the tubular portion extends;
• and
• a cartridge cap that is mounted on the cartridge body by inserting the tubular portion along the axial direction,
• wherein the cartridge body includes a first locking portion that locks to the container body in the axial direction when the cartridge body is mounted in the container body, and an insertion portion that is inserted into the container body,
• the first locking portion includes a step that is increased in diameter from the insertion portion, the step includes a flat back surface extending radially outward of the cartridge body and a corner between the flat back surface and an outer surface of the tubular portion extending toward a front from a radially outward end of the flat back surface, and the flat back surface of the step comes into contact with the container body when the cartridge body is mounted in the container body,
• the cartridge cap includes an inner surface, and a second locking portion that locks to the first locking portion in the axial direction when the cartridge cap is mounted on the cartridge body,
• the second locking portion includes a protrusion that protrudes from the inner surface of the cartridge cap,
• the second locking portion locks to the first locking portion by the protrusion being hooked onto the corner of the step, and
• the first locking portion of the cartridge body is a portion that abuts the container body and is a portion at which the second locking portion of the cartridge cap locks.