A semiconductor device and the like for maintaining a required function while suppressing unauthorized accesses are provided. The semiconductor device 100 includes a main control device 110 and a sub-control device 120. The main control device 110 includes a main memory 112 for storing main programs for receiving external signals, and a trigger signal output circuit 115 for outputting a trigger signal when an abnormal signal process differs from preset signal processing is performed. The sub-control device 120 is coupled to the main control device 110, and includes a trigger signal obtaining circuit 121 for obtaining a trigger signal, and a sub-program outputting circuit 123 for outputting a sub-program to the main control device 110 based on the obtained trigger signal.