In the SPring-8, positron beam will be used for increasing beam-lifetime in the Storage-ring. An electron/positron convertor will be installed in the middle of the Linac. For designing the convertor, experiments of positron generation and focusing were carried out with a test apparatus which was mounted in the beam-line of the JAERI-Linac. And we had been also developing a simulation code for the convertor. Simulation was already reported in JAERI-M 93-030, so this paper shows experiment results, and comparison between experiment and simulation. The experiment data are qualitatively coincident with that of simulation data. So this simulation code turned out to be available for designing the convertor. (author).