The present invention relates to a silane compound containing a perfluoro(poly)ether group, which has water repellency, oil repellency and a stain-proof property and enables the formation of a surface-treating layer having excellent frictional durability, said silane compound being represented by formula (1a) or formula (1b): (1a) A-Rf-X-SiQkY3-k; and (1b) Y3-kQkSi-X-Rf-X-SiQkY3-k (wherein A represents a C1-16 alkyl group which may be substituted by one or more fluorine atoms; Rf represents -(OC4F8)a-(OC3F6)b-(OC2F4)c-(OCF2)d- wherein a, b, c and d independently represent an integer of 0 to 200 inclusive, the sum total of a, b, c and d is at least 1, and the order of the repeating units enclosed in parentheses respectively with small letters a, b, c and d attached thereto is arbitrary in the formula; X represents a bivalent organic group; Y represents a hydroxy group, a hydrolysable group or a hydrocarbon group; Q represents -Z-SiR1 nR2 3-n; Z's in their occurrence independently represent a bivalent organic group, wherein a group capable of forming a siloxane bond along with a Si atom located at the terminal of the molecular main chain in formula (1a) or formula (1b) is excluded; R1's in their occurrence independently represent a hydroxy group or a hydrolysable group; R2's in their occurrence independently represent a C1-22 alkyl group or Q'; Q' has the same meaning as that of Q; n's in Q and Q' independently represent an integer selected from 0 to 3, wherein the sum total of n's is 1 or more; the maximum number of Si atoms to be linked linearly through the group Z in Q is 5; and k is an integer selected from 1 to 3).