A frequency-characteristic-acquisition device that inputs a time-stretched-pulse signal to a system to be measured and that acquires information about a frequency characteristic of the system on the basis of a signal output from the system is provided. The frequency-characteristic-acquisition device includes a control unit which performs control so that the time-stretched-pulse signal is expanded in a time-axis direction and output to the system, and an acquisition unit that analyzes the signal output from the system and that acquires the frequency-characteristic information.