The differential spectra of bremsstrahlung on scattering of intermediate energy (0.3–2 keV) electrons by Ar atoms are studied. The measurements are made in the 6.5–10 nm ultrasoft X-ray region (the photon energy region 190.8–124 eV), where the dynamic polarizability of an Ar atom is low. For each of the wavelengths studied it is found that as the electron energy is increased from 0.3 to 0.7 keV, the bremsstrahlung intensity increases first in direct proportion to the square root of the scattered electron energy and then decreases in inverse proportion to it on subsequent rise in the energy from 0.8 to 2 keV. The increase in the bremsstrahlung intensity with electron energy is explained in terms of the low-energy approximation by the contributions of the opened channels of atom excitation and ionization that accompany the braking effect.