A charged particle beam apparatus that can achieve both high defect-detection sensitivity and high inspection speed for a sample with various properties in a multi-beam type semiconductor inspection apparatus. The allocation of the primary beam on the sample is made changeable, and furthermore, the beam allocation for performing the inspection at the optimum inspection specifications and at high speed is selected based on the property of the sample. In addition, many optical parameters and apparatus parameters are optimized. Furthermore, the properties of the selected primary beam are measured and adjusted.