A gear pump device for rubber extrusion, which has a pair of gears (2, 2A, 2B) engaged with each other, a housing having a gear-housing bore housing a pair of the gears (2, 2A, 2B), and a bushing ring inserted in the gear-housing bore at end portions thereof in the axial direction, and whereby each of the gears (2, 2A, 2B) has a gear portion and a support-shaft portion concentrically extending from the gear portion toward both sides in the axial direction, which is characterized in that the bushing ring has a bearing and a sealing means built-in, the bearing rotatably supporting the support-shaft portion, and the sealing means disposed inward of the bearing in the axial direction and sealing between it and the outer peripheral surface of the support-shaft portion, and the sealing means includes a sealing ring which is formed from a rubber elastic body whose cross section is]-shaped and which has a cylindrical first lip portion contacting with the outer peripheral surface of the support-shaft portion, a cylindrical second lip portion disposed outside thereof in the radial direction, and a side wall portion connecting between axially outer ends of the first and second lip portions, whereby the bushing ring has a ring-shaped bushing base portion concentrically inserted in the gear-housing bore, and the inner peripheral surface of the bushing base portion has a circumferential-groove-shaped bearing-retaining groove accommodating the bearing, and a circumferential-groove-shaped sealing-means-retaining groove accommodating the sealing means and formed inside thereof in the axial direction in succession, whereby the sealing means has a ring-shaped holder concentrically inserted in the sealing-means-retaining groove, the inner peripheral surface of the holder is provided in its inside in the axial direction with a circumferential-groove-shaped seal-ring-retaining groove accommodating the sealing ring, and an inner end in the axial direction, of the seal-ring-retaining groove opens in the inside surface in the axial direction, of the holder. which has a pair of gears (2, 2A, 2B) engaged with each other, a housing having a gear-housing bore housing a pair of the gears (2, 2A, 2B), and a bushing ring inserted in the gear-housing bore at end portions thereof in the axial direction, and whereby each of the gears (2, 2A, 2B) has a gear portion and a support-shaft portion concentrically extending from the gear portion toward both sides in the axial direction, which is characterized in that the bushing ring has a bearing and a sealing means built-in, the bearing rotatably supporting the support-shaft portion, and the sealing means disposed inward of the bearing in the axial direction and sealing between it and the outer peripheral surface of the support-shaft portion, and the sealing means includes a sealing ring which is formed from a rubber elastic body whose cross section is]-shaped and which has a cylindrical first lip portion contacting with the outer peripheral surface of the support-shaft portion, a cylindrical second lip portion disposed outside thereof in the radial direction, and a side wall portion connecting between axially outer ends of the first and second lip portions, whereby the bushing ring has a ring-shaped bushing base portion concentrically inserted in the gear-housing bore, and the inner peripheral surface of the bushing base portion has a circumferential-groove-shaped bearing-retaining groove accommodating the bearing, and a circumferential-groove-shaped sealing-means-retaining groove accommodating the sealing means and formed inside thereof in the axial direction in succession, whereby the sealing means has a ring-shaped holder concentrically inserted in the sealing-means-retaining groove, the inner peripheral surface of the holder is provided in its inside in the axial direction with a circumferential-groove-shaped seal-ring-retaining groove accommodating the sealing ring, and an inner end in the axial direction, of the seal-ring-retaining groove opens in the inside surface in the axial direction, of the holder. the bushing ring has a bearing and a sealing means built-in, the bearing rotatably supporting the support-shaft portion, and the sealing means disposed inward of the bearing in the axial direction and sealing between it and the outer peripheral surface of the support-shaft portion, and the sealing means includes a sealing ring which is formed from a rubber elastic body whose cross section is]-shaped and which has a cylindrical first lip portion contacting with the outer peripheral surface of the support-shaft portion, a cylindrical second lip portion disposed outside thereof in the radial direction, and a side wall portion connecting between axially outer ends of the first and second lip portions, whereby the bushing ring has a ring-shaped bushing base portion concentrically inserted in the gear-housing bore, and the inner peripheral surface of the bushing base portion has a circumferential-groove-shaped bearing-retaining groove accommodating the bearing, and a circumferential-groove-shaped sealing-means-retaining groove accommodating the sealing means and formed inside thereof in the axial direction in succession, whereby the sealing means has a ring-shaped holder concentrically inserted in the sealing-means-retaining groove, the inner peripheral surface of the holder is provided in its inside in the axial direction with a circumferential-groove-shaped seal-ring-retaining groove accommodating the sealing ring, and an inner end in the axial direction, of the seal-ring-retaining groove opens in the inside surface in the axial direction, of the holder.