To improve productivity by efficiently reducing production loss man- hours by any working person with ease in a short period of time to reduce the production loss man-hours by defining every production loss occurred in production processes.

A system 1 supports reduction in the production losses by managing the production loss man-hours in the production processes; and the system 1 comprises a CPU 2 for controlling the whole of the system 1; a data input device 3 for inputting each data; a database 4 for storing each data; and a production loss calculation part 5 for calculating the production loss and a production loss rate based on each data stored in the database 4. The data base 4 is composed of a record data area for storing each record input from the input device 3 and a production loss data area for pre-storing kinds of the production loss, an implementation procedure of the reduction in the production loss, and a threshold to determine an evaluation criteria of the production loss.