Semiconductor device

A semiconductor device, comprising:

• a power element formed on a first semiconductor layer and having a plurality of lateral MOS transistors arranged at equal pitches in a first direction, the plurality of lateral MOS transistors having drains that extend in a second direction perpendicular to the first direction, two of the drains being shortened drains that have a width shorter in the second direction than that of the remaining drains of the plurality of lateral MOS transistors, and the plurality of lateral MOS transistors having gate electrodes that extend in the second direction, two of the gate electrodes adjacent to the two shortened drains being shortened gate electrodes that have a width shorter in the second direction than that of the remaining gate electrodes of the plurality of lateral MOS transistors;
• and
• a rectangular heat sensing element made from a second semiconductor layer isolated from the first semiconductor layer by an insulating film, the rectangular heat sensing element being configured to detect a temperature of the power element and being arranged between the two shortened drains and between the two shortened gate electrodes of the plurality of lateral MOS transistors so that at least two sides of the rectangular heat sensing element are adjacent to the power element in a plan view.