An electric device includes a plurality of circuits that operate in synchronization with a clock signal, a plurality of flip-flops each of which acquires a data value of a signal from a corresponding one of the plurality of circuits in synchronization with the clock signal and stores the acquired data value therein until receiving a next clock signal, where each flip-flop enters into a clock-disabled state, when receiving a signal at a disable terminal thereof, in which the acquired data value continues to be stored in the flip-flop, a timing controller that outputs a hold signal to the disable terminal of each flip-flop at a timing at which a corresponding circuit is desired to be diagnosed, and a plurality of diagnosis lines that are respectively provided in correspondence with the plurality of flip-flops, each diagnosis line outputting as diagnosis data a data value stored in a corresponding flip-flop.