A battery module comprising: a cell assembly including at least one battery cell; a module case accommodating the cell assembly; and a module connector mounted on a mounting surface outside the module case, electrically connected to the cell assembly, and connected to an external connector outside the module case, wherein the module connector includes: a body portion connected to a terminal coupled to the battery cell; and a fastening portion configured to have elasticity on one side of the body portion facing the mounting surface of the module case, wherein the fastening portion of the module connector is configured to impart an elastic force in a first direction parallel to the mounting surface and/or in a second direction perpendicular to the mounting surface, wherein the fastening portion of the module connector has a portion spaced apart from the body portion to form an empty space therebetween, and wherein the fastening portion of the module connector includes at least one pair of elastic supports (135a, 135b) that are convexly bent outward at both sides, and the module connector further includes a mounting end fastened to the mounting surface, and the elastic supports (135a, 135b) extend in a direction away from the body portion and are coupled to the mounting end at a portion facing the body portion. a cell assembly including at least one battery cell; a module case accommodating the cell assembly; and a module connector mounted on a mounting surface outside the module case, electrically connected to the cell assembly, and connected to an external connector outside the module case, wherein the module connector includes: a body portion connected to a terminal coupled to the battery cell; and a fastening portion configured to have elasticity on one side of the body portion facing the mounting surface of the module case, wherein the fastening portion of the module connector is configured to impart an elastic force in a first direction parallel to the mounting surface and/or in a second direction perpendicular to the mounting surface, wherein the fastening portion of the module connector has a portion spaced apart from the body portion to form an empty space therebetween, and wherein the fastening portion of the module connector includes at least one pair of elastic supports (135a, 135b) that are convexly bent outward at both sides, and the module connector further includes a mounting end fastened to the mounting surface, and the elastic supports (135a, 135b) extend in a direction away from the body portion and are coupled to the mounting end at a portion facing the body portion. a body portion connected to a terminal coupled to the battery cell; and a fastening portion configured to have elasticity on one side of the body portion facing the mounting surface of the module case, wherein the fastening portion of the module connector is configured to impart an elastic force in a first direction parallel to the mounting surface and/or in a second direction perpendicular to the mounting surface, wherein the fastening portion of the module connector has a portion spaced apart from the body portion to form an empty space therebetween, and wherein the fastening portion of the module connector includes at least one pair of elastic supports (135a, 135b) that are convexly bent outward at both sides, and the module connector further includes a mounting end fastened to the mounting surface, and the elastic supports (135a, 135b) extend in a direction away from the body portion and are coupled to the mounting end at a portion facing the body portion.