[Problem] To increase chemical spraying safety in an agricultural machine. [Solution] A system 500 for filling a chemical into a chemical tank, provided in agricultural machinery and having: a chemical tank 104； a chemical nozzle 103 that discharges objects inside the chemical tank to outside； a fluid detection unit 31 that detects when fluid refilling of the chemical tank has been completed； an air bleeding detection unit 32 that detects when an air bleeding operation has been completed； and a refilling detection unit 34 that detects when chemical refilling of the chemical tank has been completed. The system has a plurality of mutually different states and transitions to a different state corresponding to a condition. The system transitions to a spraying preparation start standby state (S4) after transitioning to at least a fluid standby state (S31), an air bleeding standby state (S32), and a chemical standby state (S34).
