To provide an adjuster for instrument which can perform the adjustment with use of an exclusive tool, does not allow removal thereof during the work, ensures excellent working efficiency and does not damage a grounding surface for a material including an elastic material.

The adjuster for instrument can adjust horizontal plane and height of the instrument when it is installed. This adjuster is provided with a receiving plate 1 for the grounding, a bolt screw 2 for mounting to the instrument and an adjusting knob 3 for adjusting height of the bolt screw. The receiving plate 1 for the grounding, adjusting knob 3 and bolt screw 2 are allocated to be removable.