A loading amount accumulation device comprising: a loading amount storage section which stores a loading amount; a loading amount calculation section which accumulates input load weight data about a transport object in a working front provided to a loading machine to the loading amount stored in the loading amount storage section, and updates the loading amount stored in the loading amount storage section by a value after being accumulated; and a difference calculation section which calculates a difference between input data about a loaded amount of a vessel provided to a transporting machine and the loading amount stored in the loading amount storage section, the loading amount accumulation device characterized by further comprising an accumulation success/failure determination section which compares an absolute value of the difference (ΔLD) calculated by the difference calculation section and a predetermined threshold value (Dth), determines that accumulation has failed when the absolute value is larger than the threshold value, and outputs a determination result; a loading amount correction section which, when the determination result indicative of an accumulation failure is output from the accumulation success/failure determination section, performs correction so as to set a loaded amount data as the loading amount, and updates the loading amount stored in the loading amount storage section by the loading amount after being subjected to the correction; and an output section which outputs the loading amount stored in the loading amount storage section, wherein the threshold value is set to be greater than 0 and less than or equal to a rated capacity of a bucket provided in the working front. a loading amount storage section which stores a loading amount; a loading amount calculation section which accumulates input load weight data about a transport object in a working front provided to a loading machine to the loading amount stored in the loading amount storage section, and updates the loading amount stored in the loading amount storage section by a value after being accumulated; and a difference calculation section which calculates a difference between input data about a loaded amount of a vessel provided to a transporting machine and the loading amount stored in the loading amount storage section, the loading amount accumulation device characterized by further comprising an accumulation success/failure determination section which compares an absolute value of the difference (ΔLD) calculated by the difference calculation section and a predetermined threshold value (Dth), determines that accumulation has failed when the absolute value is larger than the threshold value, and outputs a determination result; a loading amount correction section which, when the determination result indicative of an accumulation failure is output from the accumulation success/failure determination section, performs correction so as to set a loaded amount data as the loading amount, and updates the loading amount stored in the loading amount storage section by the loading amount after being subjected to the correction; and an output section which outputs the loading amount stored in the loading amount storage section, wherein the threshold value is set to be greater than 0 and less than or equal to a rated capacity of a bucket provided in the working front.