For an evaluation of the preoperative assessment of subungual glomus tumours, a non-invasive examination of the lesion is desirable. Previous studies, however, have not clearly demonstrated these findings. We examined two cases of subungual glomus tumours and applied the approximately 5-14 MHz broadband B-mode and C-mode ultrasound imaging methods combined with Color Doppler imaging (CDI) and B-flow imaging (BFI) to clarify the significance of the preoperative assessment. We confirmed the tumour's localization, size and depth, using B-mode and C-mode imaging; and tumour vascularity using CDI and BFI. BFI is a newly developed ultrasound technique that enhances the B-mode imaging quality of the blood flow, including high-frame-rate and high-spatial-resolution imagings. BFI revealed the exact fine blood vessels within the subungual small tumour with no blooming compared to CDI. Our results indicate that these ultrasound scanning imagings are non-invasive and nonionizing evaluation methods, and that an accurate preoperative diagnosis using these methods will result in more effective surgical excision and relief.