To provide a water stop tape which can exhibit a sufficient performance of stopping both water penetrating from the cut surface of a cable and water penetrating from its external periphery (water stop performance evaluated by the L method and the T method).

In a water stop tape prepared by forming a water-absorbing layer 2 containing water-absorbing resin particles and a rubber type binder on the surface of a support 1 made of a nonwoven fabric, the ten-point average roughness (Rz) of the surface of the layer 2 is at most 75 μm, and the maximum height (Ry) is at most 100 μm.