Diaphragm pump or diaphragm compressor

The invention relates to a diaphragm pump or a diaphragm compressor. The diaphragm pump or the diaphragm compressor comprises a shell, a working chamber, a power chamber, a diaphragm piece arranged between the working chamber and the power chamber, a piston movably arranged in the power chamber and a motor connected with the piston through a transmission system so as to drive the piston. The transmission system comprises a crankshaft; the first end of the first connecting rod is pivotally connected with the bent part of the crankshaft; the first end of the second connecting rod is pivotally connected with the second end of the first connecting rod through a first pivot; the first end of the push-pull rod is pivotally connected with the second end of the second connecting rod through a second pivot, and the second end of the push-pull rod is connected with the piston; the movement guiding seat is fixedly arranged in the shell, a movement guiding groove extending linearly is formed in the movement guiding seat,