An internal combustion engine controller comprising: an electromagnetic load controller for a fuel injection device, the electromagnetic load controller being disposed between a battery source voltage and a grounding voltage; an electromagnetic load driven by the electromagnetic load controller, a microprocessor (3; 3A; 3B; 3C) for outputting a control signal for controlling the driving of the electromagnetic load by the electromagnetic load controller; a clock input signal generating circuit for generating a clock input signal for use in working the electromagnetic load controller; an abnormality diagnosing circuit for diagnosing any physical abnormality which is different from a clock input trouble with respect to the electromagnetic load controller and the electromagnetic load; a clock trouble diagnosing circuit for diagnosing any clock input trouble of the clock input signal outputted from the clock input signal generating circuit, and a trouble/abnormality signal output circuit using an OR circuit to which an abnormality diagnosis signal outputted from the abnormality diagnosing circuit and a clock trouble diagnosis signal outputted from the clock trouble diagnosing circuit are inputted in parallel and which outputs one line of trouble/abnormality output OR signals (25', 25) resulting from the logical summing of the inputted signals, wherein, the microprocessor (3; 3A; 3B; 3C) is configured to detect the two different kinds of diagnoses according to a variation in the status level of the trouble/abnormality output OR signals (25', 25) inputted from the trouble/abnormality signal output circuit, wherein the microprocessor (3, 3A, 3B, 3C) is adapted to output a trouble/abnormality confirmation input signal to the pertinent trouble/abnormality signals output circuit according to variations in the status level of the touble/abnormality output OR signals (25', 25) inputted from the trouble/abnormality signal output circuit, and adapted to make definite any of an abnormal state, a clock trouble state and a normal state, based on the result of switching control of the status level of the pertinent trouble/abnormality output OR signals (25', 25). an electromagnetic load controller for a fuel injection device, the electromagnetic load controller being disposed between a battery source voltage and a grounding voltage; an electromagnetic load driven by the electromagnetic load controller, a microprocessor (3; 3A; 3B; 3C) for outputting a control signal for controlling the driving of the electromagnetic load by the electromagnetic load controller; a clock input signal generating circuit for generating a clock input signal for use in working the electromagnetic load controller; an abnormality diagnosing circuit for diagnosing any physical abnormality which is different from a clock input trouble with respect to the electromagnetic load controller and the electromagnetic load; a clock trouble diagnosing circuit for diagnosing any clock input trouble of the clock input signal outputted from the clock input signal generating circuit, and a trouble/abnormality signal output circuit using an OR circuit to which an abnormality diagnosis signal outputted from the abnormality diagnosing circuit and a clock trouble diagnosis signal outputted from the clock trouble diagnosing circuit are inputted in parallel and which outputs one line of trouble/abnormality output OR signals (25', 25) resulting from the logical summing of the inputted signals, wherein, the microprocessor (3; 3A; 3B; 3C) is configured to detect the two different kinds of diagnoses according to a variation in the status level of the trouble/abnormality output OR signals (25', 25) inputted from the trouble/abnormality signal output circuit, wherein the microprocessor (3, 3A, 3B, 3C) is adapted to output a trouble/abnormality confirmation input signal to the pertinent trouble/abnormality signals output circuit according to variations in the status level of the touble/abnormality output OR signals (25', 25) inputted from the trouble/abnormality signal output circuit, and adapted to make definite any of an abnormal state, a clock trouble state and a normal state, based on the result of switching control of the status level of the pertinent trouble/abnormality output OR signals (25', 25).