A pressure display apparatus that includes a detected signal processor for processing a detected signal Si obtained from a pressure detector for detecting a pressure P, a pressure value display for displaying a detected pressure value Pd at least based on a processed signal Dd obtained from the detected signal processor, and a reference point adjuster for adjusting the display for a given reference pressure value Ps. The reference point adjuster has a reference pressure value setting function to set the reference pressure value Ps for a given magnitude, a deviation value setting capability for obtaining and setting a detected pressure value Pd corresponding to the reference pressure value Ps and the deviation value Ed of the reference pressure value Ps, and a correction capability for correcting at least the detected pressure value Pd regarding the pressure P and displayed on the display based on the deviation Ed.