A terminal box that stably and surely provides a required length of play in an output line, and a method of connecting the output line. The terminal box includes a terminal strip connected to the output line, and a main body housing the terminal strip. The terminal strip includes a connecting portion electrically connected to the output line, and a play producing portion. The play producing portion has an opening receiving the output line. The main body includes a receiving hole formed at a position corresponding to the opening for receiving the output line. The play producing portion inclines relative to the connecting portion by a first angle with the output line being inserted through the receiving hole and the opening to be connected to the connecting portion, and by a second angle smaller than the first angle with the output line being connected to the connecting portion.