A curable composition including a perfluoro(poly)ether group-containing silane compound having two or more Si atoms each bonding to at least one selected from a hydroxyl and hydrolyzable group, and a group represented by: —(OC6F12)a—(OC5F10)b—(OC4F8)c—(OC3X106)d—(OC2F4)e—(OCF2)f—, wherein a, b, c and d are each independently an integer of 0 to 30, e and f are each independently an integer of 1 to 200, the sum of a, b, c, d, e and f is 5 or more, the occurrence order of the respective repeating units with the subscript a, b, c, d, e or f is not limited, a ratio of e to f is 1.0 or more, and each X10 is independently a hydrogen, fluorine or chlorine atom; an organosilicon compound having at least two —O—Rg3(s) each bonding to a Si atom, wherein each Rg3, at each occurrence, is independently a hydrogen atom or a monovalent organic group; and a catalyst.