An ultrasonograph is provided with a frequency component adjuster that adjusts spatial frequency components of original image data RAW0 of an ultrasonotomographic image. The frequency component adjuster is constituted of an unsharp image data generator, a subtraction circuit, a weighting circuit, an integration circuit, a multiplication circuit and an addition circuit. The unsharp image data generator circuit generates unsharp image data RAWi (i=1 to 5) by reducing the spatial frequency components of the original image data RAW0 in five steps. The subtraction circuit generates differential image data ΔRAWj (j=1 to 4) by subtracting the unsharp image data RAW1 from RAWi-1. The weighting circuit weights the differential image data ΔRAWj by multiplying them by respective coefficients kj (−1