To simply and precisely perform offset adjustment and scale adjustment of a galvano scanner system.

In a galvano scanner system (1), a light position detection unit (30) is mounted so as to match the scanning center of the workpiece surface (7), the light position detection unit being provided with a two-dimensional light position sensor (32) disposed in the center and four one-dimensional light position sensors (33(1)) to (33(4)) concyclically disposed at equal angles about the center of the two-dimensional light position sensor. An origin position command is given to galvano scanners (3, 4), laser light is irradiated at low output, and the offset adjustment value is calculated based on the detection output of the two-dimensional light position sensor (32). Next, the galvano scanners (3, 4) are pivoted left, right, up, and down; the perpendicularity in relation to the workpiece surface (7) is determined and the distance from the workpiece surface (7) is calculated based on the detection output of each one-dimensional light position sensor (33); and the scale adjustment value is calculated on the basis thereof. Adjustment can be carried out with good accuracy in a simple manner in comparison with the case in which such an adjustment is made in alignment with a scale on a workpiece surface while visually observing visible laser light.