A sensor control apparatus of a gas detection system includes a digital computation section having a PID computation section, a first filter section, and a second filter section as functional sections. The first filter section digitally extracts a DAC control signal (first filter signal) from a digital signal representing a supply control current Tip computed by the PID computation section. The DAC control signal is a digital signal which represents the supply control current Tip for pump current and in which noise components superimposed as a result of digital computation in the PID computation section have been attenuated.