A carton includes a top casing and a bottom casing. The top casing includes plural first sidewalls and plural first tongue parts connecting to the first sidewalls. The first tongue stripes parts are used for fixing on the inner surfaces of the adjacent first sidewalls. The bottom casing includes plural second sidewalls and plural second tongue parts connecting to the second sidewalls. The second tongue parts are used for fixing on inner surfaces of the adjacent second sidewalls. The bottom casing further includes plural reinforcing pieces respectively connected to one of the second sidewalls. The reinforcing pieces are disposed at the outside of the second sidewalls. When the top casing is coupled to the bottom casing, the reinforcing pieces are utilized for filling the gap between the top casing and the bottom casing caused by the first tongue parts.