A liquid filler for feeding a liquid into bag-shaped containers comprising: a transport unit (12, 13, 14, 15) for transporting the bag-shaped containers along a transport path including at least a liquid filling area, a sealing area, and an inspection area; container holders for holding the bag-shaped containers on the transport unit (12, 13, 14, 15); and a non-destructive inspection device for an oxygen concentration in said bag-shaped container, the non-destructive inspection device being provided in the inspection area of the transport path, the non-destructive inspection device emitting, in the inspection area of the transport path, a laser beam to a gas phase portion of the bag-shaped container filled with the liquid and measuring an oxygen concentration in the bag-shaped container based on an amount of transmitted light, the non-destructive inspection device including: a pair of right and left moving members (65, 65) provided on the opposite sides of the inspection area of the transport path such that the moving members (65, 65) are moved toward and away from the bag-shaped container by a moving device (58A, 58B); a laser emitting section that is provided on one of the moving members (65, 65) and emits the laser beam for measuring the oxygen concentration; and a laser receiving section that is provided on the other moving member and receives the laser beam wherein the non-destructive inspection device further includes: translucent inert gas chambers having an equal length on respective end faces of the laser emitting section and the laser receiving section; and a pair of tilting devices (81, 81) that are disposed on the opposite sides of the inspection area of the transport path so as to press a bottom part of the bag-shaped container from both sides by means of a container pressing member (88A, 88B) and tilt the container in a vertical plane, the container being held by the container holder so as to pivot in the vertical plane, and in measurement of the oxygen concentration in the inspection area, the tilting devices (81, 81) tilt the bag-shaped container so as to gather air in one of shoulders of an upper part of the container to a predetermined angle and brings the pair of right and left moving members (65, 65) close to each other at the one shoulder of the tilted bag-shaped container so as to bring the end faces of the laser emitting section and the laser receiving section into contact with a surface of the gas phase portion of the bag-shaped container, keeping a constant thickness of the gas phase portion while evacuating air between the end faces of the laser emitting section and the laser receiving section and the surface of the gas phase portion of the bag-shaped container. a transport unit (12, 13, 14, 15) for transporting the bag-shaped containers along a transport path including at least a liquid filling area, a sealing area, and an inspection area; container holders for holding the bag-shaped containers on the transport unit (12, 13, 14, 15); and a non-destructive inspection device for an oxygen concentration in said bag-shaped container, the non-destructive inspection device being provided in the inspection area of the transport path, the non-destructive inspection device emitting, in the inspection area of the transport path, a laser beam to a gas phase portion of the bag-shaped container filled with the liquid and measuring an oxygen concentration in the bag-shaped container based on an amount of transmitted light, the non-destructive inspection device including: a pair of right and left moving members (65, 65) provided on the opposite sides of the inspection area of the transport path such that the moving members (65, 65) are moved toward and away from the bag-shaped container by a moving device (58A, 58B); a laser emitting section that is provided on one of the moving members (65, 65) and emits the laser beam for measuring the oxygen concentration; and a laser receiving section that is provided on the other moving member and receives the laser beam wherein the non-destructive inspection device further includes: translucent inert gas chambers having an equal length on respective end faces of the laser emitting section and the laser receiving section; and a pair of tilting devices (81, 81) that are disposed on the opposite sides of the inspection area of the transport path so as to press a bottom part of the bag-shaped container from both sides by means of a container pressing member (88A, 88B) and tilt the container in a vertical plane, the container being held by the container holder so as to pivot in the vertical plane, and in measurement of the oxygen concentration in the inspection area, the tilting devices (81, 81) tilt the bag-shaped container so as to gather air in one of shoulders of an upper part of the container to a predetermined angle and brings the pair of right and left moving members (65, 65) close to each other at the one shoulder of the tilted bag-shaped container so as to bring the end faces of the laser emitting section and the laser receiving section into contact with a surface of the gas phase portion of the bag-shaped container, keeping a constant thickness of the gas phase portion while evacuating air between the end faces of the laser emitting section and the laser receiving section and the surface of the gas phase portion of the bag-shaped container.