A protective film, comprising: a first film; a second film facing the first film; and a panel protective film disposed between the first film and the second film, a first adhesive agent between the first film and the panel protective film; and a second adhesive agent between the second film and the panel protective film; wherein the panel protective film comprises a first portion and a second portion spaced apart from each other along a first direction, the first portion comprising: a first side and a second side opposite to each other along the first direction; a third side and a fourth side opposite to each other along a second direction crossing the first direction; characterized in that the first portion also comprises a first curvilinear portion connecting the second side to the fourth side, the first curvilinear portion corresponding to first respective corners of the first film and the second film and having a curved shape, wherein the first side faces the second portion, and the first curvilinear portion is disposed inside edges of the first film and the second film at the first respective corners thereof, and the panel protective film including the first curvilinear portion which is placed inside edges of the first and second films (FM1, FM2) attached to the panel protective film, such that when the first and second films (FM1, FM2) on and under the panel protective film are removed from the panel protective film, the delamination of the first and second films (FM1, FM2) is configured to start from portions (P1, P2) of the first and second films (FM1, FM2) which are disposed outside the first curvilinear portion, respectively, and have an outwardly protruding shape relative to the first curvilinear portion of the panel protective film. a first film; a second film facing the first film; and a panel protective film disposed between the first film and the second film, a first adhesive agent between the first film and the panel protective film; and a second adhesive agent between the second film and the panel protective film; wherein the panel protective film comprises a first portion and a second portion spaced apart from each other along a first direction, the first portion comprising: a first side and a second side opposite to each other along the first direction; a third side and a fourth side opposite to each other along a second direction crossing the first direction; characterized in that the first portion also comprises a first curvilinear portion connecting the second side to the fourth side, the first curvilinear portion corresponding to first respective corners of the first film and the second film and having a curved shape, wherein the first side faces the second portion, and the first curvilinear portion is disposed inside edges of the first film and the second film at the first respective corners thereof, and the panel protective film including the first curvilinear portion which is placed inside edges of the first and second films (FM1, FM2) attached to the panel protective film, such that when the first and second films (FM1, FM2) on and under the panel protective film are removed from the panel protective film, the delamination of the first and second films (FM1, FM2) is configured to start from portions (P1, P2) of the first and second films (FM1, FM2) which are disposed outside the first curvilinear portion, respectively, and have an outwardly protruding shape relative to the first curvilinear portion of the panel protective film. a first side and a second side opposite to each other along the first direction; a third side and a fourth side opposite to each other along a second direction crossing the first direction; characterized in that the first portion also comprises a first curvilinear portion connecting the second side to the fourth side, the first curvilinear portion corresponding to first respective corners of the first film and the second film and having a curved shape, wherein the first side faces the second portion, and the first curvilinear portion is disposed inside edges of the first film and the second film at the first respective corners thereof, and a first curvilinear portion connecting the second side to the fourth side, the first curvilinear portion corresponding to first respective corners of the first film and the second film and having a curved shape, wherein the first side faces the second portion, and the first curvilinear portion is disposed inside edges of the first film and the second film at the first respective corners thereof, and the panel protective film including the first curvilinear portion which is placed inside edges of the first and second films (FM1, FM2) attached to the panel protective film, such that when the first and second films (FM1, FM2) on and under the panel protective film are removed from the panel protective film, the delamination of the first and second films (FM1, FM2) is configured to start from portions (P1, P2) of the first and second films (FM1, FM2) which are disposed outside the first curvilinear portion, respectively, and have an outwardly protruding shape relative to the first curvilinear portion of the panel protective film.