An object of the invention is to provide a cosmetic mask gel sheet having a high exudation amount, by which a sufficient moisturizing feeling can be obtained as a result of penetration of water and the like through the skin to which the gel sheet is applied, which is a cosmetic mask gel sheet 1A containing at least water and a synthetic polymer forming a network structure by reacting with a cross-linking agent, in which the gel sheet includes 10 to 100 air bubbles 11 having a diameter of 0.1 mm to 1.0 mm in an area of 1 cm2 in a plan view thereof while not including air bubbles having a diameter of 3.0 mm or more.
