A wiring substrate through which a drive signal for driving a first piezoelectric element and a second piezoelectric element propagates to a discharge head which includes the first piezoelectric element having a first electrode and a second electrode, and the second piezoelectric element having a third electrode and a fourth electrode, and which discharges a liquid by driving the first piezoelectric element and the second piezoelectric element, the wiring substrate comprising: a plurality of wiring layers provided along a first direction; a via wiring that electrically couples layers of the plurality of wiring layers; a first terminal that outputs a first drive signal (COMA3); and a second terminal that outputs a second drive signal (COMA4), wherein a first wiring layer among the plurality of wiring layers includes a first wiring through which a first drive signal supplied to the first electrode for driving the first piezoelectric element such that the liquid is discharged from the discharge head propagates, among the drive signals, a second wiring through which a second drive signal supplied to the third electrode for driving the second piezoelectric element such that the liquid is discharged from the discharge head propagates, among the drive signals, and a third wiring, at least a part of which is located in an inter-wiring region between the first wiring and the second wiring, a second wiring layer among the plurality of wiring layers includes a fourth wiring through which a third drive signal supplied to the first electrode for driving the first piezoelectric element such that the liquid is not discharged from the discharge head propagates, among the drive signals, and a fifth wiring through which a reference voltage signal supplied to the second electrode and the fourth electrode and having a constant voltage value propagates, the first wiring layer and the second wiring layer are located adjacent to each other in the plurality of wiring layers, in a direction along the first direction, at least a part of the fourth wiring is located so as to overlap with the inter-wiring region, the inter-wiring region includes a wide inter-wiring region in which an inter-wiring distance between the first wiring and the second wiring is larger than a sum of a wire width of the fourth wiring and a minimum diameter of the via wiring, and a narrow inter-wiring region in which the inter-wiring distance is smaller than the sum of the wire width of the fourth wiring and the minimum diameter of the via wiring, and larger than a wire width of the via wiring, and characterized in that the third wiring is not located in the narrow inter-wiring region between a virtual line coupling the first terminal and the second terminal, and the wide inter-wiring region, in the inter-wiring region of the first wiring layer. a plurality of wiring layers provided along a first direction; a via wiring that electrically couples layers of the plurality of wiring layers; a first terminal that outputs a first drive signal (COMA3); and a second terminal that outputs a second drive signal (COMA4), wherein a first wiring layer among the plurality of wiring layers includes a first wiring through which a first drive signal supplied to the first electrode for driving the first piezoelectric element such that the liquid is discharged from the discharge head propagates, among the drive signals, a second wiring through which a second drive signal supplied to the third electrode for driving the second piezoelectric element such that the liquid is discharged from the discharge head propagates, among the drive signals, and a third wiring, at least a part of which is located in an inter-wiring region between the first wiring and the second wiring, a second wiring layer among the plurality of wiring layers includes a fourth wiring through which a third drive signal supplied to the first electrode for driving the first piezoelectric element such that the liquid is not discharged from the discharge head propagates, among the drive signals, and a fifth wiring through which a reference voltage signal supplied to the second electrode and the fourth electrode and having a constant voltage value propagates, the first wiring layer and the second wiring layer are located adjacent to each other in the plurality of wiring layers, in a direction along the first direction, at least a part of the fourth wiring is located so as to overlap with the inter-wiring region, the inter-wiring region includes a wide inter-wiring region in which an inter-wiring distance between the first wiring and the second wiring is larger than a sum of a wire width of the fourth wiring and a minimum diameter of the via wiring, and a narrow inter-wiring region in which the inter-wiring distance is smaller than the sum of the wire width of the fourth wiring and the minimum diameter of the via wiring, and larger than a wire width of the via wiring, and characterized in that the third wiring is not located in the narrow inter-wiring region between a virtual line coupling the first terminal and the second terminal, and the wide inter-wiring region, in the inter-wiring region of the first wiring layer.