In an injector driving apparatus, a driving circuit supplies a current individually to each coil of multiple injectors, a current detection element detects the current flowing in a common current flow path, which is common to the coils, a current supply period guard part forcibly stops the current supplied from the driving circuit to the coil upon determination that a measured period reached a predetermined set period based on a detection result of the current detection element, and a diagnosis part operates in a period of no fuel injection to check whether the current supply period guard part normally stops the current supplied to the coil, by continuously supplying the current to the coil for only a short period, which disables the injector to open a valve, and sequentially switches over the coils.