Abstract: A safeguard cap 1 is attached to an injection needle 10 that includes a hollow needle 11 and a holding member 12 for attaching the hollow needle 11 to a medical device. The safeguard cap 1 includes a housing part 2 for housing the hollow needle 11, a base 3 to be attached to the holding member 12, and a joint (bridges 4) for joining the housing part 2 and the base 3 to each other. The housing part 2 is formed in a tubular shape, with one end thereof being open and the other being closed. The joint is formed so as to be broken when external force for rotating the housing part 2 about its longitudinal axis that serves as a central axis is applied to the housing part 2, with the base 3 having been attached to the holding member 12.