FIG. 1 is a perspective view of an embodiment of a casing for measurement instrument showing my new design; FIG. 2 is a top view thereof; FIG. 3 is a front view thereof; FIG. 4 is a first side view thereof; FIG. 5 is a back view thereof; FIG. 6 is a bottom view thereof; and, FIG. 7 is a second side view thereof.