This paper presents an experimental study of the propagation characteristics of a laser pulse in a biased Bi12TiO20 on a nanosecond time scale. Experimental investigations on the self-bending phenomenon in such a crystal with a narrow pulse at b.lambda=532 nm are first reported and confirm our theoretical numerical results: no bending is observed for a 10 ns pulse in the range of kV/cm for the external electric field applied. Regarding these results, systematic investigations have been achieved to study the self-focusing process on a nanosecond time-scale. We evidence that a laser pulse can be self-focused during the very short time of the pulse duration and we investigate the influence on this phenomenon of different parameters, such as the electric field applied