An engine fluid heating apparatus, preventing failure in heating fluid, is provided. A control device opens a sub switch during an initial opening period (“IOP”) after closing a main switch, and the control device closes the sub switch during an initial closing period (“ICP”) after the IOP. Circuit normality is displayed by turning on an indicator lamp when a heater feeding circuit is electrically conducted via a bypass electric circuit during the IOP. Heater feeding is displayed by turning off the indicator lamp when power is supplied to the electric heater via a trunk electric circuit during the ICP. Circuit abnormality is displayed by turning off the indicator lamp when the heater feeding circuit is not electrically conducted via the bypass electric circuit during the IOP, and the circuit abnormality display is held by keeping the indicator lamp off during the ICP immediately after the IOP.