An ink jet apparatus includes a plurality of actuators that discharge a liquid from a discharge port according to a driving signal input to an input terminal; a driving selector that outputs a drive switch control signal; a plurality of drive switches that connect or disconnect the input terminal of the actuator and a driving signal source according to the drive switch control signal for the actuator, and allow the driving signal to pass therethrough and input the driving signal to the input terminal when the input terminal and the driving signal source are connected; a detection circuit that detects a voltage of the input terminal when being connected to the input terminal; and a plurality of detection switches that connect or disconnect the input terminal of the actuator and the detection circuit on the basis of the drive switch control signal or the driving signal passed through the drive switch.