A hermetic compressor may include a cylinder having an elliptical inner circumferential surface; a roller eccentric from the inner circumferential surface; and at least one vane withdrawn towards the inner circumferential surface when the roller is rotated to divide a compression chamber. On the basis of a contact point where the inner circumferential surface and an outer circumferential surface are closest, a first center line passes through a center of the cylinder, an ellipse positioned at a first side of the first center line and forming the inner circumferential surface is a first ellipse, a center point of the first ellipse is a first center point, an ellipse positioned at a second side of the first center line and forming the inner circumferential surface is a second ellipse, a center point of the second ellipse is a second center point, and the first center point and the second center point are spaced apart from the center.