A winter tire containing a central vertical groove which extends along a tire equator C, and rib portions 6a and 6b having sipes S are formed on the opposite sides of the central vertical groove. At a groove edge line 3E of the central vertical groove, reference pitches P each comprises a main portion extending from an outermost origin N1 in a tire axial direction to a terminal end N2 closest to the tire equator, and an auxiliary portion 3b having a length in the tire circumferential direction smaller than that of the main portion 3a and passes through said origin N1 from said terminal end N2, and the reference pitches P are repeated in the tire circumferential direction into a zigzag configuration. A tire circumferential direction length of the main portion is 60% or more of a tire circumferential direction length of the reference pitch P.