To enable adjustment of the pouring volume of the contents in a large size of liquid container provided with a particularly large mouth.

A female screw part 21 which can be screwed in a container mouth 3 is formed at the inside of a fitting cylinder 2 at the lower part of a cap body 1. A hermetical seal plate 42 surrounded by a cut groove 41 partitioning an outflow hole 4 having a size to adjust the outflow rate is provided at the top plate 11 of the cap body 1 and also a picking tab 43 formed so as to rise on the upper face of the seal plate 42 is provided there. And further, a guide cylinder 5 is formed at the upper face of the cap body 1 so as to surround the seal plate 42.