A conveyor apparatus comprising: a plurality of outgoing path side guide pulleys and a plurality of returning path side guide pulleys disposed along a helical conveyance path extending in a vertical direction and arranged at positions where inflection points of the conveyance path are formed such that the plurality of outgoing path side guide pulleys and the plurality of returning path side guide pulleys form the inflection points; an endless conveyor belt wound around the plurality of outgoing path side guide pulleys in turn along the helical conveyance path in a bent state where the endless conveyor belt is folded in two in a width direction in such a manner that an upper edge portion of the endless conveyor belt is supported by the plurality of outgoing path side guide pulleys, the endless conveyor belt being wound around the plurality of returning path side guide pulleys in turn along the helical conveyance path in the bent state where the endless conveyor belt is folded in two in the width direction in such a manner that the upper edge portion is supported by the plurality of returning path side guide pulleys, and further, the endless conveyor belt being folded back at turning positions of an upper side and a lower side of the conveyance path and being in an expanded state where the endless conveyor belt is expanded in the width direction in a vicinity of each of the turning positions; a pair of an upper side turning pulley and a lower side turning pulley configured to support and guide the endless conveyor belt to stretch at the respective turning positions; a drive motor configured to drive at least one of the plurality of outgoing path side guide pulleys, the plurality of returning path side guide pulleys, and the pair of upper side turning pulley and the lower side turning pulley, characterized in that, on the outer circumference surface of the outgoing path side guide pulley, a first recessed portion having a trapezoidal cross sectional shape is formed endlessly in the circumferential direction, and on a lower side of the first recessed portion, a second recessed portion having a trapezoidal cross sectional shape is formed endlessly in the circumferential direction, wherein an end portion on one side of the conveyor belt constituting the upper edge portion of the conveyor belt is formed into a trapezoidal cross sectional shape having a complementary shape with the first recessed portion, and fitted in the first recessed portion to be supported, wherein an end portion on the other side of the conveyor belt constituting the upper edge portion of the conveyor belt is formed into a trapezoidal cross sectional shape having a complementary shape with the second recessed portion, and fitted in the second recessed portion to be supported. a plurality of outgoing path side guide pulleys and a plurality of returning path side guide pulleys disposed along a helical conveyance path extending in a vertical direction and arranged at positions where inflection points of the conveyance path are formed such that the plurality of outgoing path side guide pulleys and the plurality of returning path side guide pulleys form the inflection points; an endless conveyor belt wound around the plurality of outgoing path side guide pulleys in turn along the helical conveyance path in a bent state where the endless conveyor belt is folded in two in a width direction in such a manner that an upper edge portion of the endless conveyor belt is supported by the plurality of outgoing path side guide pulleys, the endless conveyor belt being wound around the plurality of returning path side guide pulleys in turn along the helical conveyance path in the bent state where the endless conveyor belt is folded in two in the width direction in such a manner that the upper edge portion is supported by the plurality of returning path side guide pulleys, and further, the endless conveyor belt being folded back at turning positions of an upper side and a lower side of the conveyance path and being in an expanded state where the endless conveyor belt is expanded in the width direction in a vicinity of each of the turning positions; a pair of an upper side turning pulley and a lower side turning pulley configured to support and guide the endless conveyor belt to stretch at the respective turning positions; a drive motor configured to drive at least one of the plurality of outgoing path side guide pulleys, the plurality of returning path side guide pulleys, and the pair of upper side turning pulley and the lower side turning pulley, on the outer circumference surface of the outgoing path side guide pulley, a first recessed portion having a trapezoidal cross sectional shape is formed endlessly in the circumferential direction, and on a lower side of the first recessed portion, a second recessed portion having a trapezoidal cross sectional shape is formed endlessly in the circumferential direction, wherein an end portion on one side of the conveyor belt constituting the upper edge portion of the conveyor belt is formed into a trapezoidal cross sectional shape having a complementary shape with the first recessed portion, and fitted in the first recessed portion to be supported, wherein an end portion on the other side of the conveyor belt constituting the upper edge portion of the conveyor belt is formed into a trapezoidal cross sectional shape having a complementary shape with the second recessed portion, and fitted in the second recessed portion to be supported.