An agricultural machine tire, comprising: lug blocks that are disposed in a tread portion and are formed alternately on both sides of a tire equatorial plane in a tire circumferential direction; and a central rib that extends in the tire circumferential direction at a tire width direction central portion of the tread portion and to which end portions of the lug blocks on the tire equatorial plane side are integrally connected, and when a tire width direction length of the central rib from connecting portions with the end portions to the tire equatorial plane is taken as a first rib width, wherein the connecting portions are sections at which sections of the lug blocks having a substantially constant width in the tire circumferential direction end and at which the width in the tire circumferential direction starts to increase, and a shortest tire width direction length of the central rib from end edges of the central rib positioned on the tire width direction opposite side from the connecting portions across the tire equatorial plane to the tire equatorial plane is taken as a second rib width, the first rib width is configured to be greater than the second rib width; wherein a tire width direction length, from the connecting portions to tire width direction outside ends of the lug blocks continuous with those connecting portions, is configured to be greater than a connecting portion rib width (w) that is the sum of the first rib width and the second rib width, characterized in that the lug blocks are inclined toward the opposite side of a tire rotational direction from an inner side in the tire width direction to an outer side in the tire width direction. lug blocks that are disposed in a tread portion and are formed alternately on both sides of a tire equatorial plane in a tire circumferential direction; and a central rib that extends in the tire circumferential direction at a tire width direction central portion of the tread portion and to which end portions of the lug blocks on the tire equatorial plane side are integrally connected, and when a tire width direction length of the central rib from connecting portions with the end portions to the tire equatorial plane is taken as a first rib width, wherein the connecting portions are sections at which sections of the lug blocks having a substantially constant width in the tire circumferential direction end and at which the width in the tire circumferential direction starts to increase, and a shortest tire width direction length of the central rib from end edges of the central rib positioned on the tire width direction opposite side from the connecting portions across the tire equatorial plane to the tire equatorial plane is taken as a second rib width, the first rib width is configured to be greater than the second rib width; wherein a tire width direction length, from the connecting portions to tire width direction outside ends of the lug blocks continuous with those connecting portions, is configured to be greater than a connecting portion rib width (w) that is the sum of the first rib width and the second rib width, characterized in that the lug blocks are inclined toward the opposite side of a tire rotational direction from an inner side in the tire width direction to an outer side in the tire width direction.