A divergent gas-puff Z pinch has been devised for the realization of an efficient soft x-ray point source. In this device, a divergent hollow annular gas puff is ejected outward from the surface of the inner electrode, and the plasma is compressed three-dimensionally to generate a soft x-ray point source. In the SHOTGUN III-U device at Nihon University, the power supply was enhanced, and experiments were conducted over a larger current range. The peak current at the charging voltage of -25 kV was -190 kA. Ar was used as the discharge gas. The self-contraction process of the plasma was investigated in detail using a gated camera. Near the peak current, local contraction occurred in front of the inner electrode. The contraction velocity of the plasma was 5.5 × 10⁴ m/s. As the plasma contracted, the discharge current decreased. The energy input was analyzed by induction acceleration. The net input energy was found to be 750 J, which corresponded to 13.3% of the stored energy of the capacitor, 5630 J. The soft x-ray source was observed using a soft x-ray CCD camera. A point source was observed 7 mm in front of the inner electrode. The size of the source was 35 μm in the axial direction and 14 μm in the radial direction.