PURPOSE: To offer the information of usage state release from other devices at the generation of a failure, by discriminating the propriety of use of a resource in high speed, through the provision of a managing means of the resouce usage state and a storage means of devices to release the usage state.

CONSTITUTION: In case of resource usage state managing hardware (HWLK), one device is selected between two MCUs at the same time and an HWLK bit number specific to the address bit is designated. When the resource is in use, an FF31 of the MCU shows the usage state and the data is returned to the requested adress. When the resource is not used, an output of an OR gate 35 is 0 and a bit corresponding to the FF31 is 1. The state of the HWLK bit is transmitted and received on signal lines 42, 44 on the MCUs. In case of reset request, number designation information is transmitted to a switching gate 36 and the other MCU. The information from the other MCU enters the switching gate 36, one information is given to a decoder 37 and the FF31 is reset.