The present invention relates to a pouch having an internal straw, which stores liquid in a space between a first sheet material (101) and a second sheet material (102), the edges of which are welded, and in which a straw (111) is built-in. A baseline (120) where the first sheet material (101) and the second sheet material (102) meet in a floor portion inside the pouch has a straight upward gradient from a bottom point (121) to form an inverted triangular shape between the bottom point (121) and the straight upward gradient. Moreover, a lower end (111A) of the straw (111) is positioned at the bottom point (121), and the lower end of the straw is attached to the first sheet material (101) or the second sheet material (102) to maintain the position of the lower end of the straw.