PURPOSE: To provide an input protection circuit having a high electrostatic breakdown voltage without enlarging an area.

CONSTITUTION: High concentration n-type diffused region 117 and p-type diffused region 119 are formed in such a manner that the width parallel to the contact surface of a p-type conductive well 116 and an n-type conductive well 118 is longer than the vertical length, in the rectangular shape as the plan view at almost the center area between the p-type conductive well 116 and n-type conductive well 118 formed adjacently. An aluminum wiring 115 is formed crossing the surface of the n-type diffused layer 117 and p-type diffused region 119 through an insulating film 122 and it is connected to the diffused region with contact portions 120, 120 having the width size longer than that of the region of aluminum wiring 115.