Abstract: The present disclosure relates to an apparatus for attaching and detaching an auxiliary battery of a travel carrier, which is detachably mounted in the travel carrier regardless of a size and type of the auxiliary battery thereby efficiently responding to airport security screening and realizing user-friendly convenience. The apparatus includes: a body mounted in the travel carrier and having an accommodating part; a battery casing inserted into the accommodating part of the body and detachably housing the auxiliary battery; a controller provided on an upper part of the battery casing, having a first connection port at an upper part and a second connection port at a lower part, and outputting power input through the second connection port to the first connection port; and a connector accommodated in the battery casing and connecting the second connection port and an output port of the auxiliary battery.