A membrane switch can attach an elastically deformable dome to a board in a reliable manner such that the dome is not detached even if a fixing sheet is made thinner and smaller and therefore has a smaller footprint. This switch has: a dome (110) that is formed projecting toward the surface and that is dented opposite toward the back surface by elastic deformation; and a flexible fixing sheet (120) that has a back surface of an adhesive face pasted to the entire face of the surface of the dome (110). The fixing sheet (120) fixes the dome (110) in a predetermined position of a board (4) by means of a stretching part (122) which stretches radially outer to the dome (110), from an outer rim (112) of the dome (110), in a direction virtually orthogonal to a direction in which the dome (110) projects. A plurality of slits (130) formed in the fixing sheet (120) at predetermined intervals along the outer rim (112) of the dome (110), prevent a stretching part (122) of the fixing sheet (120), from joining with a dome covering part (121) which is a portion above the dome (110) that continues in the radial direction of the dome (110).