An induction heating apparatus includes a first interventional device and a second interventional device. A current detector detects a level of a total panel current flowing in an organic EL panel. A return-flow alarm-triggering pressure is specified, and when pressure of the return flow in the system is higher than or equal to the specified pressure, a return-flow alarm is triggered. Upon impact, the tube with the sprinkler is forced upward within a housing against expansion of a spring, which normally urges the tube and sprinkler into a storage position within the housing. The tilling implement comprises at least one tine plate.