PROBLEM TO BE SOLVED: To provide a puncture unit and a chemical solution administration unit in which an outer needle can be easily inserted, and a puncture device can be easily detached from a cradle device.SOLUTION: A puncture device 3 comprises a body 41 and a puncture mechanism 42. The puncture mechanism 42 comprises an inner needle 67, a needle holding part 73, a protection cover 74, arm parts 76, 77, and an energization member 68. The protection cover 74 is arranged so as to cover the periphery of a needle tip of the inner needle 67 and stores the needle tip of the inner needle 67. The arm parts 76, 77 move the protection cover 74 to a position storing the needle tip of the inner needle 67. The puncture device 3 performs all of the following operations with a single operation: a puncture operation for puncturing a living body with an outer needle 6 and the inner needle 67 in the puncture mechanism 42 and extracting the inner needle 67 from the outer needle 6； a separation operation for separating the body 41 from a cradle device 2； and a cover operation for moving the protection cover 74 by the arm parts 76, 77 to a position storing the needle tip of the inner 67.
