A head module includes lines of head chips, each head chip having energy-generating elements for discharging liquid and electrodes for electrically connecting the energy-generating elements to a control substrate, and a wiring board having wires for electrically connecting the electrodes to the control substrate. The head module drives the energy-generating elements through the wiring board to discharge liquid. The wiring board includes connecting sections connecting the wires to the respective electrodes, common wire sections joining some of the wires that are common to the head chips, and a terminal section connecting the wires to the control substrate at one side of the wiring board. The wires in the connecting and terminal sections are arranged in a single-layer structure along a horizontal direction. The wires in the common wire sections are arranged in a multi-layer structure in which portions of the wires are stacked in the vertical direction.