Phase-contrast imaging of living tissues is important for investigating biological structures and functions. The phasecontrast
scanning optical microscope using annular illumination and image processing has been developed as a new tool
for visualizing phase objects. This microscope has excellent features, such as separate phase and amplitude imaging,
reducing multiscattering effects and spherical aberration-free imaging. Using a figure-8-shaped spatial-frequency filter
with sign correction in order to extract linear phase-contrast components, we observed the phase-contrast structures of
biological tissue samples and evaluated the microscope’s imaging features.