Our preceding works reported the development of a high spatial and temporal resolution imaging system by using a current biased kinetic inductance detector (CB-KID) with the use of a delay-line technique. We called this system as a delay-line CB-KID, and succeeded in imaging of neutron events caused by the nuclear reaction and hot spots produced by using the delay-line CB-KID system. It was essentially important for our proposal to use a superconducting stripline to guide the pulsed signal where the signal propagates at a constant fast velocity along the stripline. In the present study, we intend to measure a propagation velocity of the signal along the stripline precisely to compare with the theoretical prediction of the signal propagation, which was recently developed with a superconducting waveguide SIS model by Koyama and Ishida [11]. Our present measurements showed a good agreement between the theoretical predictions and the experimental results on the propagation velocity as a function of temperature.