In a liquid discharging apparatus, a head unit includes a driving element, a first circuit that controls drive of the driving element based on a first signal including a first data signal and a second data signal, and a first conversion circuit that converts a first optical signal into the first data signal, and converts a second optical signal into the second data signal, a driving circuit includes a second circuit that outputs a second signal including a third data signal and a fourth data signal, a second conversion circuit that converts the third data signal into the first optical signal, and converts the fourth data signal into the second optical signal, a first cable, and a second cable, the first cable propagates the first optical signal during a first period, and the second cable propagates the second optical signal during a second period.