To provide an alignment tester correcting device, capable of making the cost necessary for correction work of an alignment tester to be reduced and allowing a user to efficiently carry out correction work of the alignment tester.

The alignment tester correcting device includes correction blocks 51, 52, 53; a support member 40 for supporting the correction blocks 51, 52, 53; an inclination adjusting mechanism 20 for adjusting an inclination of the support member 40 in the right-and-left directions; a laser marking device 60 for irradiating a first laser light 61 and a second laser light 62; a first light receiving device 71 that receives the first laser light 61; when the correction blocks 51, 52, 53 are positioned at respective reference positions P1, P2, P3; a second light-receiving device 72 that receives the second laser light 62, when the correction blocks 51, 52, 53 are positioned on respective reference positions P1, P2, P3; a right-and-left sliding mechanism 32 for moving the support member 40 along the right-and-left directions; and a rotating mechanism 33 for making the support member 40 turn, by making the vertical direction to be the axial direction of a rotating center.