A backpressure passage rotary compressor, comprising: a drive motor configured to generate a rotational force; a rotational shaft coupled to the drive motor to transfer a rotational force; a cylinder through which the rotational shaft passes, the cylinder configured to form a refrigerant accommodating space in which a refrigerant can be accommodated in a central portion thereof, and provided with a suction port and a discharge port in a radial direction; first and second blocks (131, 132) respectively installed on one side and the other side of the cylinder in a direction in which the rotational shaft extends; a roller located in the cylinder so that one side thereof is in contact with a contact point portion of an inner circumferential surface of the cylinder, the roller configured to rotate together with the rotational shaft to form a compression chamber in the cylinder; a plurality of vane slots formed in the roller, the vane slots provided with a pocket portion arranged at an inner end thereof and a slide portion connected to the compression chamber from the pocket portion; a plurality of vanes inserted into the vane slots, the plurality of vanes formed to protrude by backpressure applied to the vane slots to be in contact with the inner circumferential surface of the cylinder, and configured to partition the compression chamber into a plurality of chambers; and a backpressure passage formed on an outer circumferential surface of the roller, the backpressure passage provided with a backpressure inlet disposed in front of the vane slot with respect to a rotational direction of the roller and a backpressure outlet formed in the pocket portion to allow the compression chamber and the pocket portion to communicate with each other, characterized in that at least one of an inner side surface of the first block and an inner side surface of the second block is provided with a discharge pressure groove configured to communicate with the pocket portion at a portion where a straight line extending from the contact point portion to the rotational shaft and a rotational path of the pocket portion cross each other. a drive motor configured to generate a rotational force; a rotational shaft coupled to the drive motor to transfer a rotational force; a cylinder through which the rotational shaft passes, the cylinder configured to form a refrigerant accommodating space in which a refrigerant can be accommodated in a central portion thereof, and provided with a suction port and a discharge port in a radial direction; first and second blocks (131, 132) respectively installed on one side and the other side of the cylinder in a direction in which the rotational shaft extends; a roller located in the cylinder so that one side thereof is in contact with a contact point portion of an inner circumferential surface of the cylinder, the roller configured to rotate together with the rotational shaft to form a compression chamber in the cylinder; a plurality of vane slots formed in the roller, the vane slots provided with a pocket portion arranged at an inner end thereof and a slide portion connected to the compression chamber from the pocket portion; a plurality of vanes inserted into the vane slots, the plurality of vanes formed to protrude by backpressure applied to the vane slots to be in contact with the inner circumferential surface of the cylinder, and configured to partition the compression chamber into a plurality of chambers; and a backpressure passage formed on an outer circumferential surface of the roller, the backpressure passage provided with a backpressure inlet disposed in front of the vane slot with respect to a rotational direction of the roller and a backpressure outlet formed in the pocket portion to allow the compression chamber and the pocket portion to communicate with each other, characterized in that at least one of an inner side surface of the first block and an inner side surface of the second block is provided with a discharge pressure groove configured to communicate with the pocket portion at a portion where a straight line extending from the contact point portion to the rotational shaft and a rotational path of the pocket portion cross each other.