An insulated gate bipolar transistor comprising: an insulating gate type field effect transistor portion having a source region and a drain region, which are opposed to each other sandwiching a body region of a conductivity type opposite to that of the source region and that of the drain region, as well as a gate electrode, which is opposed to said body region sandwiching a gate insulating film (4, 4a); a stabilizing plate, made of a conductor or of a semiconductor, which is opposed to said drain region sandwiching an insulating film (4, 4b) for a plate and which forms, together with said drain region, a capacitor; and a semiconductor substrate having a first main surface and a second main surface that are opposed to each other, wherein said body region is uniformly distributed over the entirety of the first main surface, wherein: a plurality of transistors of the same type as said insulating gate type field effect transistor are arranged side by side; one said stabilizing plate is arranged in a region sandwiched by two of said insulating gate type field effect transistors; said semiconductor substrate has a trench for a gate formed at the first main surface, and a trench for an emitter formed at the first main surface, said gate electrode filling said trench for a gate, said stabilizing plate filling said trench for an emitter, wherein an upper surface of stabilizing plate is positioned within trench for an emitter; and a stabilizing plate capacitor formed between said stabilizing plate and said drain region has a capacitance greater than that of a gate-drain capacitor formed between said gate electrode and said drain region, wherein in said stabilizing plate is electrically connected to said source region wherein an impurity diffusion region of a conductivity type opposite to that of the source region and that of the drain region is formed in the body region at the first main surface between said trench for a gate and said trench for an emitter and has an impurity concentration higher than the impurity concentration of said body region. an insulating gate type field effect transistor portion having a source region and a drain region, which are opposed to each other sandwiching a body region of a conductivity type opposite to that of the source region and that of the drain region, as well as a gate electrode, which is opposed to said body region sandwiching a gate insulating film (4, 4a); a stabilizing plate, made of a conductor or of a semiconductor, which is opposed to said drain region sandwiching an insulating film (4, 4b) for a plate and which forms, together with said drain region, a capacitor; and a semiconductor substrate having a first main surface and a second main surface that are opposed to each other, wherein said body region is uniformly distributed over the entirety of the first main surface, wherein: a plurality of transistors of the same type as said insulating gate type field effect transistor are arranged side by side; one said stabilizing plate is arranged in a region sandwiched by two of said insulating gate type field effect transistors; said semiconductor substrate has a trench for a gate formed at the first main surface, and a trench for an emitter formed at the first main surface, said gate electrode filling said trench for a gate, said stabilizing plate filling said trench for an emitter, wherein an upper surface of stabilizing plate is positioned within trench for an emitter; and a stabilizing plate capacitor formed between said stabilizing plate and said drain region has a capacitance greater than that of a gate-drain capacitor formed between said gate electrode and said drain region, wherein in said stabilizing plate is electrically connected to said source region wherein an impurity diffusion region of a conductivity type opposite to that of the source region and that of the drain region is formed in the body region at the first main surface between said trench for a gate and said trench for an emitter and has an impurity concentration higher than the impurity concentration of said body region. a plurality of transistors of the same type as said insulating gate type field effect transistor are arranged side by side; one said stabilizing plate is arranged in a region sandwiched by two of said insulating gate type field effect transistors; said semiconductor substrate has a trench for a gate formed at the first main surface, and a trench for an emitter formed at the first main surface, said gate electrode filling said trench for a gate, said stabilizing plate filling said trench for an emitter, wherein an upper surface of stabilizing plate is positioned within trench for an emitter; and a stabilizing plate capacitor formed between said stabilizing plate and said drain region has a capacitance greater than that of a gate-drain capacitor formed between said gate electrode and said drain region, wherein in said stabilizing plate is electrically connected to said source region wherein an impurity diffusion region of a conductivity type opposite to that of the source region and that of the drain region is formed in the body region at the first main surface between said trench for a gate and said trench for an emitter and has an impurity concentration higher than the impurity concentration of said body region.