A vehicle key assembly may include a main body case; an emergency key including a key portion and a knob connected to the key portion and provided to be introduced into the main body case; a restraining member; and a manipulator configured to operate the restraining member, wherein the knob includes: a knob case connected to the key portion and configured to close an opening of the main body case in a state of being accommodated in the main body case; a key ring member mounted on the knob case to be introduced into or retracted from the knob case to be protruded to an outside of the main body case; and one or more elastic members provided in the knob case and configured to press the key ring member in a protrusion direction in which the key ring member is protruded.