To provide a key head cover with excellent decorating features, ease of handling, and reliability by forming it to be easily detachable from a key head part without impairing decorating features and to have the connection function of the key head part to a key holder to arbitrarily attach a desired decoration thereon without preparing it as a blank key.

This key head cover 10 attached to the key head part for operably holding a key body 101 for locking-unlocking a lock mechanism comprises a ring member 11 connectable to the key holder, a hooking member connected to the ring member and a connection hole for the key holder of the key head part, and a cover member 13 in which a slit for containing the key head part together with the hooking member and the ring member is formed and having, on both surfaces, a flat surface part 14 for indicating various types of information.