To provide a screwed joint for a pressure vessel appricable for the connection part of a pressure vessel such as an outer shell of a solid rocket motor or the like by which such an inconvenience that the screw connection part is deformed and broken in the radius and axial directions is arizon depending on the degree of the inner pressure because usual joints are connected by the screwed force of the male and female screws.

The screw joint for a pressure vessel is constituted of a fitting section projected from at least one front end of the male part or female part and a fitting groove cut on the separation face of the pressure vessel opposite to the fitting section. In this way, the inconvenience is eliminated and the function of the pressure vessel can be retained and it is made lightweight.