An injection molding machine comprising: a movable platen; a rear platen; a link mechanism which has a plurality of links (151, 152, 153, 154), one end connected to the movable platen, and the other end connected to the rear platen; a lubricant supply device configured to supply a lubricant to at least one connection portion of a connection portion which connects the movable platen and the link (151, 152, 153, 154) to each other, a connection portion which connects the links (151, 152, 153, 154) to each other, and a connection portion which connects the rear platen and the link (151, 152, 153, 154) to each other; and a control unit configured to control the lubricant supply device, wherein at least one connection portion of the connection portions includes a bush, a connection pin (50, 51, 52, 53, 54) which is inserted into the bush, a supply path (62, 63) through which a lubricant is supplied to a bearing clearance which is a clearance between the bush and the connection pin (50, 51, 52, 53, 54), and a discharge path (67, 68) through which the lubricant is discharged from the bearing clearance, the lubricant supply device includes a supply mechanism which is connected to the supply path (62, 63) and configured to supply the lubricant, characterized in that the lubricant supply device further includes a discharge mechanism including a recovery pump, the discharge mechanism being connected to the discharge path (67, 68) and being configured to discharge the lubricant, and the control unit includes a detection unit configured to detect an operation state of the discharge mechanism and a suction state of air performed by the recovery pump, and a determination unit configured to determine whether or not to operate the supply mechanism based on a detection result of the detection unit. a movable platen; a rear platen; a link mechanism which has a plurality of links (151, 152, 153, 154), one end connected to the movable platen, and the other end connected to the rear platen; a lubricant supply device configured to supply a lubricant to at least one connection portion of a connection portion which connects the movable platen and the link (151, 152, 153, 154) to each other, a connection portion which connects the links (151, 152, 153, 154) to each other, and a connection portion which connects the rear platen and the link (151, 152, 153, 154) to each other; and a control unit configured to control the lubricant supply device, wherein at least one connection portion of the connection portions includes a bush, a connection pin (50, 51, 52, 53, 54) which is inserted into the bush, a supply path (62, 63) through which a lubricant is supplied to a bearing clearance which is a clearance between the bush and the connection pin (50, 51, 52, 53, 54), and a discharge path (67, 68) through which the lubricant is discharged from the bearing clearance, a bush, a connection pin (50, 51, 52, 53, 54) which is inserted into the bush, a supply path (62, 63) through which a lubricant is supplied to a bearing clearance which is a clearance between the bush and the connection pin (50, 51, 52, 53, 54), and a discharge path (67, 68) through which the lubricant is discharged from the bearing clearance, the lubricant supply device includes a supply mechanism which is connected to the supply path (62, 63) and configured to supply the lubricant, characterized in that the lubricant supply device further includes a discharge mechanism including a recovery pump, the discharge mechanism being connected to the discharge path (67, 68) and being configured to discharge the lubricant, and a supply mechanism which is connected to the supply path (62, 63) and configured to supply the lubricant, characterized in that the lubricant supply device further includes a discharge mechanism including a recovery pump, the discharge mechanism being connected to the discharge path (67, 68) and being configured to discharge the lubricant, and the control unit includes a detection unit configured to detect an operation state of the discharge mechanism and a suction state of air performed by the recovery pump, and a determination unit configured to determine whether or not to operate the supply mechanism based on a detection result of the detection unit. a detection unit configured to detect an operation state of the discharge mechanism and a suction state of air performed by the recovery pump, and a determination unit configured to determine whether or not to operate the supply mechanism based on a detection result of the detection unit.