A fulcrum bearing device for a pulley arm wherein a sleeve is inserted in a shaft hole formed in a boss portion of the pulley arm, wherein washers are attached to two respective end portions of the sleeve so as to be opposed to two respective end surfaces of the boss portion in an axial direction, wherein the sleeve is fixed in position by means of a bolt which is inserted through the sleeve, screwed into a member to which the pulley arm is attached, and tightened, whereby the pulley arm is pivotally supported, wherein the shaft hole of the boss portion is formed, at two respective end portions of the shaft hole, with seal receiving recesses having diameters larger than a diameter of the shaft hole, and wherein seal members are incorporated in the respective seal receiving recesses, so as to prevent a foreign object from going into the boss portion from outside, and each of the seal members is made of an elastic material, the fulcrum bearing device being characterized in that each of the seal members comprises a cylindrical portion press-fitted on an inner diameter surface of the seal receiving recess, an inwardly extending annular portion integrally connected with an outer side end of the cylindrical portion, and a tapered radial lip extending obliquely inwardly from an inner periphery of the annular portion inside of the cylindrical portion, and having a distal end portion kept in elastic contact with an outer diameter surface of the sleeve, wherein the annular portion of each of the seal members has an outer side surface provided, on an inner peripheral portion of the outer side surface, with an axial lip extending obliquely outwardly and having a distal end portion kept in elastic contact with an inner side surface of a corresponding one of the washers, wherein each of the washers is formed with an annular recessed step in the inner side surface of the washer at an outer peripheral portion thereof opposed to a corresponding one of the end surfaces of the boss portion, the annular recessed step defining, inside the annular recessed step, a circular protrusion fitted in a corresponding one of the seal receiving recesses, wherein the annular recessed steps have side surfaces opposed to the respective end surfaces of the boss portion with minute gaps defined between the respective side surfaces and the respective end surfaces of the boss portion, and configured to restrict an axial movement of the pulley arm, and wherein the axial lips are kept in elastic contact with side surfaces of the respective circular protrusions. wherein washers are attached to two respective end portions of the sleeve so as to be opposed to two respective end surfaces of the boss portion in an axial direction, wherein the sleeve is fixed in position by means of a bolt which is inserted through the sleeve, screwed into a member to which the pulley arm is attached, and tightened, whereby the pulley arm is pivotally supported, wherein the shaft hole of the boss portion is formed, at two respective end portions of the shaft hole, with seal receiving recesses having diameters larger than a diameter of the shaft hole, and wherein seal members are incorporated in the respective seal receiving recesses, so as to prevent a foreign object from going into the boss portion from outside, and each of the seal members is made of an elastic material, the fulcrum bearing device being characterized in that each of the seal members comprises a cylindrical portion press-fitted on an inner diameter surface of the seal receiving recess, an inwardly extending annular portion integrally connected with an outer side end of the cylindrical portion, and a tapered radial lip extending obliquely inwardly from an inner periphery of the annular portion inside of the cylindrical portion, and having a distal end portion kept in elastic contact with an outer diameter surface of the sleeve, wherein the annular portion of each of the seal members has an outer side surface provided, on an inner peripheral portion of the outer side surface, with an axial lip extending obliquely outwardly and having a distal end portion kept in elastic contact with an inner side surface of a corresponding one of the washers, wherein each of the washers is formed with an annular recessed step in the inner side surface of the washer at an outer peripheral portion thereof opposed to a corresponding one of the end surfaces of the boss portion, the annular recessed step defining, inside the annular recessed step, a circular protrusion fitted in a corresponding one of the seal receiving recesses, wherein the annular recessed steps have side surfaces opposed to the respective end surfaces of the boss portion with minute gaps defined between the respective side surfaces and the respective end surfaces of the boss portion, and configured to restrict an axial movement of the pulley arm, and wherein the axial lips are kept in elastic contact with side surfaces of the respective circular protrusions.