A wire-grid polarizer includes metal reflectors which are embedded in a large number of grooves formed in a one-dimensional grid pattern in the same direction and with the same period in the front surface of a transparent sheet, wherein the average width (a) of the metal reflectors is 200 nm or less, the ratio (b/a) of the average thickness (b) of the metal reflectors from the front side of the sheet to the tip in the backward direction to the above average width (a) is 4 to 25, in any cross-section perpendicular to the surface of the sheet, the shape of each of the metal reflectors in the vicinity of the tip in the thickness direction is such that it gradually becomes thinner in a linear or smoothly curved shape toward the tip, and the ratio of the average length (c) toward the tip of portions that gradually become thinner toward the tip to the above average width (a) is 1.2 or more.