A port-equipped bag (1) includes a bag body (3) formed in a bag shape with a sheet, and a cylindrical port member (2) attached to the bag body (3), and an inner plug (50) and a cap (4) can be attached to the port member (2). The port member (2) includes an attaching target portion (25) that is covered by the cap (4) in a case in which the cap (4) is attached thereto and an annular lip (26) protruding outward from the port member (2). The lip (26) has an annular engagement surface (26A) facing the bag body (3), and the engagement surface (26A) has an angle of 45° to 135° with respect to an outer peripheral surface of the attaching target portion (25) in a cross section in an axial direction of the attaching target portion (25).
