Threaded bottle-shaped can and manufacturing method thereof

A metallic threaded bottle-shaped can, comprising:

• a cylindrical trunk portion;
• a shoulder portion that is formed continuously upwardly from an upper end of the trunk portion in such a manner that an outer diameter is gradually reduced toward an upper side;
• a cylindrical neck portion having an opening on an upper end, that is formed continuously upwardly from an upper central end of the shoulder portion;
• and
• a thread as a helical ridge that is formed around the neck portion,
• wherein the thread includes an upper incomplete thread portion that is formed at an upper end of the thread,
• a height of the ridge of the upper incomplete thread portion is shorter than an average value of the entire thread, and increases gradually toward the average value, and
• a length of the upper incomplete thread portion in a circumferential direction of the neck portion between:
• a first point at which a height of the ridge is one-half of the average height;
• and a second point at which a height of the ridge is one-quarter of the average height, is set in such a manner that an angle between a line drawn between the first point and a center point of the neck portion, and a line drawn between the second point and the center point of the neck portion falls within a range from 20 degrees to 60 degrees.