A mold clamping apparatus for an injection molding machine, comprising: a motor; a ball screw operated by the motor, the ball screw being oriented in a horizontal direction; a crosshead coupled to the ball screw so that, when the ball screw rotates, the crosshead moves forwards or backwards; a stationary plate and a rear plate connected to a tie bar; and a movable plate disposed between the stationary plate and the rear plate, the movable plate being moved forwards or backwards by links comprising a first link, a second link and a third link, wherein, when the movable plate is moved backwards, a first end of the first link forms a B-joint along with a first-side extension of the rear plate, and the first link is oriented leftward and downwards based on the B-joint; a second end of the second link forms a D-joint along with the crosshead, and the second link is oriented leftward and upwards based on a G-joint while connecting the G-joint to the D-joint; a first end of the third link forms an A-joint along with a second end of the first link, the third link is oriented rightward and upwards based on the A-joint, and a second end of the third link forms a C-joint along with a second-side extension of the movable plate, when the movable plate is moved forwards, the first link the first end of which forms the B-joint along with the first-side extension of the rear plate is horizontally oriented rightward based on the B-joint; the second end of the second link forms the D-joint along with the crosshead, and the second link is oriented upwards based on a G-joint while connecting the G-joint to the D-joint; and the first end of the third link forms the A-joint along with the second end of the first link, the third link is oriented rightward based on the A-joint, and the second end of the third link forms the C-joint along with the second-side extension of the movable plate, and the first link, the second link and the third link comprise first links, second links and third links provided both above and below the ball screw when viewed from a side view characterized in that, the first link has a portion that, in a position where the movable plate is moved backwards, protrudes rightward from a right side surface of the first link toward the third link and that a first end of the second link forms the G-joint along with the portion of the first link. a motor; a ball screw operated by the motor, the ball screw being oriented in a horizontal direction; a crosshead coupled to the ball screw so that, when the ball screw rotates, the crosshead moves forwards or backwards; a stationary plate and a rear plate connected to a tie bar; and a movable plate disposed between the stationary plate and the rear plate, the movable plate being moved forwards or backwards by links comprising a first link, a second link and a third link, wherein, when the movable plate is moved backwards, a first end of the first link forms a B-joint along with a first-side extension of the rear plate, and the first link is oriented leftward and downwards based on the B-joint; a second end of the second link forms a D-joint along with the crosshead, and the second link is oriented leftward and upwards based on a G-joint while connecting the G-joint to the D-joint; a first end of the third link forms an A-joint along with a second end of the first link, the third link is oriented rightward and upwards based on the A-joint, and a second end of the third link forms a C-joint along with a second-side extension of the movable plate, when the movable plate is moved forwards, the first link the first end of which forms the B-joint along with the first-side extension of the rear plate is horizontally oriented rightward based on the B-joint; the second end of the second link forms the D-joint along with the crosshead, and the second link is oriented upwards based on a G-joint while connecting the G-joint to the D-joint; and the first end of the third link forms the A-joint along with the second end of the first link, the third link is oriented rightward based on the A-joint, and the second end of the third link forms the C-joint along with the second-side extension of the movable plate, and the first link, the second link and the third link comprise first links, second links and third links provided both above and below the ball screw when viewed from a side view a first end of the second link forms the G-joint along with the portion of the first link.