A projection type cathode ray tube includes a phosphor screen, a cathode, G1, G2 and a main lens composed of first, second and third electrodes. The first and third electrodes are supplied with an anode voltage of the phosphor screen, and the second electrode is supplied with a focus voltage lower than the anode voltage. An inside diameter of an opening in a phosphor screen side end of the second electrode is from 14 mm to 18 mm, and the phosphor screen side end of the second electrode is disposed within the third electrode. An aperture diameter D mm in the G1 electrode and an axial length L mm of the second electrode satisfy the following inequalities: L mm60D mm+27.6 mm, L mm-646D mm+396.3 mm, D mm0.44 mm, and L mm75 mm.