A switching element control circuit includes: a third electrode voltage control part which controls a third electrode voltage; a first electrode current detection part which detects a first electrode current which flows through the switching element; a memory part which stores information including an initial threshold voltage and an initial first electrode current, and a drain current characteristic of a threshold voltage; and a threshold voltage calculation part which calculates a threshold voltage at a time of operating the switching element based on information including the first electrode current, the initial threshold voltage, and an initial first electrode current, and information relating to the first electrode current characteristic of the threshold voltage, wherein the third electrode voltage control part controls the third electrode voltage based on a threshold voltage at the time of operating the switching element calculated by the threshold voltage calculation part.