Microcomputer cross-monitoring system and microcomputer cross-monitoring method

The disclosed microcomputer cross-monitoring system performs cross-monitoring between a first microcomputer (11) and a second microcomputer (12), wherein if resetting of the second microcomputer is implemented as a result of an occurrence of an anomaly of the second microcomputer, during the reset, instead of monitoring of the main microcomputer by a monitoring function of the second microcomputer, monitoring of the main microcomputer by a substitute monitoring function (142) mounted in the interior of the main microcomputer is carried out. Accordingly, a microcomputer cross-monitoring system is achieved which is capable of preventing loss in the product value while maintaining reliability as a system.