To provide a dustproof device and a measuring instrument using the same, minimizing an influence on a movable member.

This dustproof device is provided with: a first bellows member 31 and a second bellows member 32 for sandwiching a stage 2; a guide mechanism 50 arranged along the moving direction of the stage 2 on both end sides in the width direction orthogonal to the expansion direction of the bellows members 31 and 32 and guiding a stage side end part of the bellows members 31 and 32; and a wire 60 wrapped around between a connecting member 33 of the stage 2 and the first bellows member 31 and a connecting member 34 of the second bellows member 32 so that the first bellows member 31 and the second bellows member 32 expand by synchronizing with the movement of the stage 2. The wire 60 is arranged on the axis along the moving direction of the stage 2 by passing through the substantial center of gravity of the stage 2.