PURPOSE: To effect change in the conveying speed easily by changing only the number of gear tooth of a bevel gear in the conveying wheel section, in which a bevel gear unit is arranged to project outward at the side of an inner wheel in the conveying wheel section so that the bevel gear unit is geared with a bevel gear of a driving shaft.

CONSTITUTION: A transmission shaft 32 is rotated when a motor 31 is powered, each of bevel gears 34 and 35, and bevel gears 26 attached on a driving shaft 22 by way of the driving shaft 22 are consequently rotated permitting a conveyor wheel 5 to be simultaneously rotated, since these bevel gears are in mesh of a bevel gear 21 of the inner wheel 8 in each of conveying wheel 5. Accordingly, a cargo starts being conveyed, when placed on a group of conveying wheel 5 which is arranged on the both sides. In this case, a partial change in the conveying speed can be obtained by chaning the outer diameter, i.e. the number of the gear tooth of the bevel gear 21 of the inner wheel 8 in the conveying wheel 5 concerned. That is, decrease (increase) in the number of the gear tooth of the above-mentioned gear 21 results in increase (decrease) in the conveying speed.