To provide a cold cathode ionization vacuum gauge using a permanent magnet as a member for inducing discharge, and readily generating discharges by arranging the permanent magnet on a pole piece.

The cold cathode ionization vacuum gauge 1 includes: a cylindrical cathode 43 having an opening formed on one end; a rod-shaped anode 44, arranged in an internal space of the cathode; magnetic means 45a, 45b for forming a magnetic field orthogonal to the electric field between the anode and the cathode, and generating discharge between the anode and the cathode; a pole piece 14, removably fitted to an opening edge of the cathode for covering the opening; and the permanent magnet 4 arranged on the pole piece 14.