Provided are a load drive apparatus in which a semiconductor chip using DTI for inter-element separation is mounted, the load drive apparatus being capable of diagnosing a dielectric strength voltage of the DTI and highly reliable and a failure diagnosis method of the load drive apparatus. There is provided a load drive apparatus in which a semiconductor chip is mounted. The semiconductor chip includes a load drive output unit formed on a semiconductor substrate. The load drive output unit has a first region where an MOSFET that controls load driving is formed and a second region insulated and separated by DTI from the first region and includes a first leakage current detection element provided in the first region, a second leakage current detection element provided in the second region, and a failure detection unit that determines a failure of the load drive output unit.