A slide operation device is comprised of a movement guide of a rod-shape, and a moving block that slides on the movement guide for setting an electric parameter as a measurement value in accordance with a movement amount or position of the moving block in a slide direction along the movement guide. The movement guide is composed of a slide bar and a magnetic scale material. The slide bar is formed of a rigid member with strength difficult to be bent, and formed with a groove extending along the slide direction. The magnetic scale material is made from a resin and a magnetic material and filled in the groove. The slide bar is formed with a concave which is deeper than the groove and which extends in a direction perpendicular to the slide direction, and the magnetic scale material is also filled in the concave.