A controller of an electromagnetic valve driving circuit include a switching element connected to an electromagnetic valve solenoid, a cutoff circuit for cutting off a connection between a power supply and the switching element, and a current detecting unit for detecting a current flowing in the solenoid. The controller includes an abnormality diagnosing unit for outputting a cutoff command to the cutoff circuit for cutting off the connection between the power supply and the switching element, and outputting a switching command causing the switching element to perform a switching operation when a predetermined diagnosis condition is satisfied, and determining that the cutoff circuit normally operates when the solenoid current is less than a threshold value and determining that the cutoff circuit operates abnormally when the solenoid current is greater than or equal to the threshold value while outputting the cutoff command and the switching command.