Abstract: A linear gauge includes a contact member having a lower tip to be positioned facing a workpiece; an air slider including a cylinder surrounding the contact member with a clearance left between them, and configured to eject air such that the contact member is supported movably in a vertical direction; a scale that detects a height position of the contact member; a casing accommodating therein the contact member, the air slider, and the scale; an evacuation portion formed in an upper portion of the cylinder such that the ejected air is evacuated into the casing; and a communication channel communicating an inlet, which is formed in an upper portion of the contact member, and an outlet, which is formed in the lower tip of the contact member, with each other inside the contact member.

Abstract: A linear gauge includes a contact member having a lower tip to be positioned facing a workpiece; an air slider including a cylinder surrounding the contact member with a clearance left between them, and configured to eject air such that the contact member is supported movably in a vertical direction; a scale that detects a height position of the contact member; a casing accommodating therein the contact member, the air slider, and the scale; an evacuation portion formed in an upper portion of the cylinder such that the ejected air is evacuated into the casing; and a communication channel communicating an inlet, which is formed in an upper portion of the contact member, and an outlet, which is formed in the lower tip of the contact member, with each other inside the contact member.