A miniature movable device comprises a movable part (a mirror, a movable rod, support arms, and a movable comb tooth electrode) formed on a substrate and adapted to be displaced in a direction parallel to the sheet surface of the substrate, a fixing part formed and fixedly mounted on the substrate, and hinges, each having its opposite ends connected to the movable part and the fixing part and assuming two flexural conditions which are reversed in flexural, the hinges being effective to maintain the movable part at two positions by a self-holding action when it assumes either flexural condition. The substrate is formed with wall surfaces which are disposed oppositely to the opposite surfaces of the hinges over a movable range of the hinges. Spacings between the hinges and the wall surfaces disposed on the opposite sides thereof are equal to each other at every point along the lengthwise direction of the hinges when the hinges assume one of the two flexural conditions (an initial condition assumed upon manufacture). This eliminates an inconvenience that during a drying step which follows a wet etching operation during the manufacture, a liquid may remain on only one side of the hinges to cause the hinges to be held attracted to the wall surfaces.