To provide a key holding implement capable of holding a key from falling with extremely simple constitution without needing to provide the key with an exclusive holding part, and to provide a key management case.

The key holding implement 15 holding the key K through a through hole K1 of the key or an annular holder 50 comprises a pair of holding bodies 35 each with one end formed as a fixed end and with the other end formed as a free end. The holding bodies are disposed with a predetermined space and provided with mutually butting projection parts 36 at the free end side relative parts. These projection parts comprise inclined parts 42 with the tips located on the fixed end side rather than base parts, and the annular holder 50 is located on the base part side of the projection part 36 due to self-weight when holding the key K.