A container includes a film portion (4) at one end thereof. The container includes a liquid outlet port at the other end on an opposite side of the one end. A liquid is discharged through the liquid outlet port. The container further includes a box-shaped portion (3). A direction in which a straight line passing through each of a center position of the film portion (4) and a center position of the liquid drug outlet port extends is defined as a first direction (DR1). The box-shaped portion (3) has a cross section that is orthogonal to the first direction (DR1) and formed in an approximately rectangular shape. In at least one of corner portions (11) of the approximately rectangular shape, the box-shaped portion (3) is provided with a groove (12) extending in parallel to the first direction (DR1).