To provide a membrane switch that has a high insulation breakdown voltage and can perform normal operation for a long time.

In the membrane switch, the size of a first and a second contact points 4, 5 are made different in size and the smaller contact point out of the first and second contact points 4, 5 is positioned at the center part side of the larger contact point, and thereby the protruded parts 4a, 5a of the first and second contact points 4, 5 are arranged not to be opposed each other. Hence, the gap between the first and second contact points 4, 5 can be made large than before, and thus a membrane switch having a high insulation breakdown voltage can be provided.