FSUE Research and Development Institute of Mechanical Engineering (Russian: ФГУП Научно-исследовательский институт машиностроения), also known as NIIMash, is a Russian rocket engine design and manufacturing company specialized in small thrusters.

It is located in the city of Nizhnyaya Salda, Sverdlovsk Oblast.

It started as the B-175 factory of the NII-1 research institute, where Mikhail G. Mironov directed the development of liquid rocket engines research and testing.

NIIMash has an extensive experience in design of testing stands, measurement and control as well as certifications.

They also have a line of custom built air separation plants.