机械增压器又称超级增压器（supercharger），是一种用于内燃机的强制进气装置。

与涡轮增压器相比，最大的区别就在于空气压缩机的驱动方式，涡轮增压器利用引擎废气推动之，而机械增压器则利用发动机曲轴产生的扭矩。但是，机械增压器的设计初衷与涡轮增压器大体相同，都是透过空气压缩机为发动机吸入更多空气，辅以加大燃油的供给量，提高发动机的输出功率。

常见的机械增压器有离心式机械增压器、双螺旋式机械增压器（又称“罗茨式增压器”或“罗茨风机”）和“鲁式”机械增压器（Roots）。

由于早期的内燃机用增压器全部都是机械增压，在发明之初称为超级增压器（Supercharge）。后来涡轮增压发明，为了便于区分，涡轮增压器被称为“Turbo Supercharger”（涡轮式机械增压器），机械增压则被称为“Mechanical Supercharger”。久而久之，两者就分别被简化为Turbocharger与Supercharger了

A supercharger is an air compressor that increases the pressure or density of air supplied to an internal combustion engine. This gives each intake cycle of the engine more oxygen, letting it burn more fuel and do more work, thus increasing power.

Power for the supercharger can be provided mechanically by means of a belt, gear, shaft, or chain connected to the engine's crankshaft. When power is provided by a turbine powered by exhaust gas, a supercharger is known as a turbosupercharger – typically referred to simply as a turbocharger or just turbo. Common usage restricts the term supercharger to mechanically driven units.