This invention provides a horizontal MOS transistor capable of improving current drivability and reducing ON resistance by optimizing the gate wiring structure and the disposition structure of source/drain layers. First gate wirings are disposed in the X direction at a pitch Y1 in the Y direction and second gate wirings 12 are disposed in the Y direction with two pieces as a pair such that they meander at a pitch X1 in the X direction. The meandering of the second gate wiring 12 is formed so as to sandwich the bent portions 14 substantially in the center of the pitch Y1. A bottle-like shape diffusion layer region in which the wide-width region and narrow-width region are combined is sectioned by adjacent first and second wirings. A contact 16 for connecting the diffusion layer region to the wiring layer 18 is disposed in the wide-width region and wiring layers 18 are disposed such that two rows run in parallel in the X direction. A diffusion layer region is a different electrode region from diffusion layer regions adjacent on four sides thereby forming a MOS transistor. Consequently, a horizontal MOS transistor excellent in current drivability for each unit region and having a slight ON resistance is constructed.