To provide a slide operating device easy to manufacture, of reduced cost, and capable of preventing dust from adhering to a magnetic scale.

The slide operating device is provided with a box-like retainer 1 long extended in one direction, a magnetic scale 50 fitted on an inner face of the retainer so as to be extended along a length direction of the retainer, and a mobile body 30 carrying a magnetic sensor 55 at a position facing the magnetic scale and in free sliding movement in the retainer length direction. It is so structured that the magnetic sensor 55 is to output a movement signal in accordance with sliding movement of the mobile body 30, and the retainer 1 is provided with an upper wall 24 located at a lower side of a member having a slit 611 formed enabling the mobile body 30 to slide, and a sidewall 21 formed vertically from a side edge of the upper wall, with the magnetic scale 50 fitted on an inner face of the upper wall 24.