SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To provide a semiconductor device that allows improvement of ESD discharge capability without increasing special processes for ESD countermeasures and a dedicated mask.SOLUTION: An ESD protection element 21 for high breakdown voltage composed of an HV transistor 23 of a MOSFET structure and a protection resistor circuit 25, and an ESD protection element 22 for low breakdown voltage composed of an LV transistor 24 of the MOSFET structure and a protection resistor circuit 26 are formed in a predetermined region on a substrate. The protection resistor circuit 25(26) has the same structure as the HV transistor 23 (the LV transistor 24) except that both resistive drift regions 16(17) that are separately formed on a surface portion of a well 2(3) so as to face to each other with interposed a gate electrode 8b(8d) therebetween are electrically connected to each other by a low-concentration drift region 5c(5d) with the same conductivity type as the resistive drift regions 16(17).