A carry-on luggage includes a casing having wheels rotatably mounted on a side face of the casing to allow the casing to move freely, a first recessed area defined in the side face thereof and a second recessed area defined in a side face of the casing to communicate with the first recessed area, a main board provided with a third recessed area, and a first and a second auxiliary handles securely and slidably received in the third recessed area to be able to extend out of the main board. The second auxiliary handle is able to extend out of the third recessed area and the first auxiliary handle is able to extend out of the third recessed area only when the main board is extended out of the first recessed area and pivoted relative to the casing.