A resin molding device comprising: a mold including a molding space suitable for forming a thin and soft resin molded product by injection molding and comprising a concave mold and a convex mold (21a, 121a, 221a); and an air ejector (22, 122, 222) to remove, by air injection, the resin molded product formed in the molding space from a molding surface (25a, 25b) of the mold, wherein: the air ejector (22, 122, 222) includes an air passage (24a, 24b, 124a, 224a) formed inside at least one of the concave mold and convex mold (21a, 121a, 221a) of the mold, an air outlet (26a, 26b, 126a, 226a) opened to a molding-space side of the air passage (24a, 24b, 124a, 224a) to inject air between the resin molded product formed in the molding space and the molding surface (25a, 25b), a movable valve (27a, 27b, 127a, 227a) movably accommodated inside the air passage (24a, 24b, 124a, 224a) and biased by a bias member (29a, 29b, 129a, 229a) in a direction in which the air outlet (26a, 26b, 126a, 226a) is closed, an air supply path through which the air is supplied from an air supply source to the air passage (24a, 24b, 124a, 224a), an air pressure detector provided on the air supply path to detect a pressure of the air [[;]], and a controller; for removing the resin molded product from the molding space, the controller supplies the air to the air passage (24a, 24b, 124a, 224a) via the air supply path at an air pressure larger than a bias force of the bias member (29a, 29b, 129a, 229a) to move the movable valve (27a, 27b, 127a, 227a) to protrude from the air outlet (26a, 26b, 126a, 226a) and open the air outlet (26a, 26b, 126a, 226a); and after removing the resin molded product, the controller supplies the air to the air passage (24a, 24b, 124a, 224a) via the air supply path at an air pressure smaller than the bias force of the bias member (29a, 29b, 129a, 229a) to detect the smaller air pressure by the air pressure detector so as to detect an operation state of the movable valve (27a, 27b, 127a, 227a). a mold including a molding space suitable for forming a thin and soft resin molded product by injection molding and comprising a concave mold and a convex mold (21a, 121a, 221a); and an air ejector (22, 122, 222) to remove, by air injection, the resin molded product formed in the molding space from a molding surface (25a, 25b) of the mold, wherein: the air ejector (22, 122, 222) includes an air passage (24a, 24b, 124a, 224a) formed inside at least one of the concave mold and convex mold (21a, 121a, 221a) of the mold, an air outlet (26a, 26b, 126a, 226a) opened to a molding-space side of the air passage (24a, 24b, 124a, 224a) to inject air between the resin molded product formed in the molding space and the molding surface (25a, 25b), a movable valve (27a, 27b, 127a, 227a) movably accommodated inside the air passage (24a, 24b, 124a, 224a) and biased by a bias member (29a, 29b, 129a, 229a) in a direction in which the air outlet (26a, 26b, 126a, 226a) is closed, an air supply path through which the air is supplied from an air supply source to the air passage (24a, 24b, 124a, 224a), an air pressure detector provided on the air supply path to detect a pressure of the air [[;]], and a controller; for removing the resin molded product from the molding space, the controller supplies the air to the air passage (24a, 24b, 124a, 224a) via the air supply path at an air pressure larger than a bias force of the bias member (29a, 29b, 129a, 229a) to move the movable valve (27a, 27b, 127a, 227a) to protrude from the air outlet (26a, 26b, 126a, 226a) and open the air outlet (26a, 26b, 126a, 226a); and after removing the resin molded product, the controller supplies the air to the air passage (24a, 24b, 124a, 224a) via the air supply path at an air pressure smaller than the bias force of the bias member (29a, 29b, 129a, 229a) to detect the smaller air pressure by the air pressure detector so as to detect an operation state of the movable valve (27a, 27b, 127a, 227a). the air ejector (22, 122, 222) includes an air passage (24a, 24b, 124a, 224a) formed inside at least one of the concave mold and convex mold (21a, 121a, 221a) of the mold, an air outlet (26a, 26b, 126a, 226a) opened to a molding-space side of the air passage (24a, 24b, 124a, 224a) to inject air between the resin molded product formed in the molding space and the molding surface (25a, 25b), a movable valve (27a, 27b, 127a, 227a) movably accommodated inside the air passage (24a, 24b, 124a, 224a) and biased by a bias member (29a, 29b, 129a, 229a) in a direction in which the air outlet (26a, 26b, 126a, 226a) is closed, an air supply path through which the air is supplied from an air supply source to the air passage (24a, 24b, 124a, 224a), an air pressure detector provided on the air supply path to detect a pressure of the air [[;]], and a controller; for removing the resin molded product from the molding space, the controller supplies the air to the air passage (24a, 24b, 124a, 224a) via the air supply path at an air pressure larger than a bias force of the bias member (29a, 29b, 129a, 229a) to move the movable valve (27a, 27b, 127a, 227a) to protrude from the air outlet (26a, 26b, 126a, 226a) and open the air outlet (26a, 26b, 126a, 226a); and after removing the resin molded product, the controller supplies the air to the air passage (24a, 24b, 124a, 224a) via the air supply path at an air pressure smaller than the bias force of the bias member (29a, 29b, 129a, 229a) to detect the smaller air pressure by the air pressure detector so as to detect an operation state of the movable valve (27a, 27b, 127a, 227a).