To provide a plastic container which can be completely sealed in a two-step sealing method, does not increase the number of manufacturing processes and components, requires a short period of time for making a mold, and is inexpensive in manufacturing cost.

The plastic container having a cap screwed with a neck of a container body is equipped with an annular groove 112 with a chevron-shaped cross section approximately at a center position of an annular top surface 111 of the neck 110 of the container body 100. A contact seal ring 211 with a chevron-shaped cross section and a tip formed in a curved surface which brings the annular groove into tight contact with the tip is provided to hang on a position on an internal surface of a top plate of the cap 200 facing the groove. A contact seal ring 212 with a U-shaped cross section for bringing an inner periphery at the tip of the neck of the container body into linearly tight contact with an outer peripheral surface is provided to hang on a position on an internal surface of a top plate inside the contact seal ring 212.