The present invention discloses a linear compressor in which a piston is driven by a linear motor and linearly reciprocated inside a cylinder to suck, compress and discharge refrigerants. Even though load is varied, the linear compressor performs the operation in a resonance state by estimating a natural frequency of the piston and synchronizing an operation frequency of the linear motor with the natural frequency of the piston, and efficiently handles the load by varying a compression capacity by changing a stroke of the piston.