A problem to be solved is to reduce a leakage current between the gate and the source. Provided is a trench type FET, where a thickness Δ1 of an oxide insulating layer O1 that is closer to the inner side than a line extending upward from the outer peripheral side of a nitride insulating layer N is ½ of a thickness d of the nitride insulating layer N or more; and a thickness Δ2 of an oxide insulating layer O3 between the upper end of the nitride insulating layer N and a gate region is ½ of the thickness d of the nitride insulating layer N or more.