Gas inlet valve for a compressor, in particular for a rotary compressor, comprising: a housing, which has a gas inlet portion for aspirating a gas and a gas outlet portion, which can be operatively fluidically connected to a gas inlet portion as required, for passing the aspirated gas to a compressor block of the compressor; a valve device arranged between the gas inlet portion and the gas outlet portion and comprising a valve body and a valve seat, the valve body being positioned tightly on the valve seat in a closed operating state of the valve device, and the valve body being raised from the valve seat in an open operating state of the valve device; a piston device, which has a first piston portion and a second piston portion differing from the first piston portion, the first piston portion being guided displaceably in a first cylinder portion of the housing, and the second piston portion being guided displaceably in a second cylinder portion of the housing differing from the first cylinder portion, the first cylinder portion having a diameter DZ1, the second cylinder portion having a diameter DZ2, the first piston portion having a diameter DK1 tuned to the diameter DZ1 of the first cylinder portion, the second piston portion having a diameter DK2 tuned to the diameter DZ2 of the second cylinder portion; and a piston rod which is mounted displaceably in the housing and which mechanically couples the valve body of the valve device to the piston device, a fluid line operatively fluidically connecting a first cylinder chamber of the first cylinder portion to the gas outlet portion, a control pressure being applicable to a second cylinder chamber of the second cylinder portion so as to raise the valve body from the valve seat, characterised in that the diameter DK1 of the first piston portion is greater than the diameter DK2 of the second piston portion, and in that an effective pressurisable area of the first piston portion is at least 2 times an effective pressurisable area of the second piston portion. a housing, which has a gas inlet portion for aspirating a gas and a gas outlet portion, which can be operatively fluidically connected to a gas inlet portion as required, for passing the aspirated gas to a compressor block of the compressor; a valve device arranged between the gas inlet portion and the gas outlet portion and comprising a valve body and a valve seat, the valve body being positioned tightly on the valve seat in a closed operating state of the valve device, and the valve body being raised from the valve seat in an open operating state of the valve device; a piston device, which has a first piston portion and a second piston portion differing from the first piston portion, the first piston portion being guided displaceably in a first cylinder portion of the housing, and the second piston portion being guided displaceably in a second cylinder portion of the housing differing from the first cylinder portion, the first cylinder portion having a diameter DZ1, the second cylinder portion having a diameter DZ2, the first piston portion having a diameter DK1 tuned to the diameter DZ1 of the first cylinder portion, the second piston portion having a diameter DK2 tuned to the diameter DZ2 of the second cylinder portion; and a piston rod which is mounted displaceably in the housing and which mechanically couples the valve body of the valve device to the piston device, a fluid line operatively fluidically connecting a first cylinder chamber of the first cylinder portion to the gas outlet portion, a control pressure being applicable to a second cylinder chamber of the second cylinder portion so as to raise the valve body from the valve seat, characterised in that the diameter DK1 of the first piston portion is greater than the diameter DK2 of the second piston portion, and in that an effective pressurisable area of the first piston portion is at least 2 times an effective pressurisable area of the second piston portion.