A delay measuring device according to the present invention comprises a memory cell, a delay element and a selector. The memory cell is provided with a non-inversion output terminal and an inversion output terminal, and the memory cell fetches a data value inputted from outside in synchronization with a clock, retains the fetched data value and outputs the retained data value from the non-inversion output terminal and the inversion output terminal. The delay element is connected to the inversion output terminal. The selector selects one of the data value and a delayed data value outputted from the delay element and supplies the selected data value to the memory cell. In the present invention, a comparison result of making a comparison between a delay amount generated in the delayed data value and a time length defined based on the clock is outputted from the non-inversion output terminal.