The separated DTL (SDTL) which accelerates a H i ion beam from 50 to 190 MeV is one of the main components in the injection linac for the JAERI/KEK joint project. The resonant frequency is 324 MHz. It consists of 32 independent tanks. The first two tanks of the SDTL were constructed. The tank cylinders are made with the newly established copper electroforming method on the steel. The high power conditioning of SDTLs has been completed successfully. The maximum input peak-power was about 500 kW, which is approximately three times of the required power. The repetition rate of the rf pulse is 50 Hz and the pulse length is 600 „sec. The time we spent for the conditioning for each tank is about 30 hours. The required conditioning period is extremely short.