A computing system for building a virtual factory, comprising: a database configured to store modeling data; a data analysis module; and a virtual factory building module, wherein the virtual factory building module is configured to: build the virtual factory in which a progress situation of a first work performed from a first portion to a second portion is displayed, based on the modeling data and a time difference between an output time of a first signal and an output time of a second signal, which is calculated based on: the first signal output when a product is at the first portion on one or more facilities (311, 312, 313, 314, 315) monitored from a first location outside of the one or more facilities (311, 312, 313, 314, 315) used in a real factory, wherein the first signal is output from a first monitoring device configured to recognize the product and wherein the first signal includes information about an image of the first portion taken from the first location when the product is at the first portion, and the second signal output when the product is at the second portion on the one or more facilities (311, 312, 313, 314, 315) monitored from a second location outside of the one or more facilities (311, 312, 313, 314, 315), wherein the second signal is output from a second monitoring device configured to recognize the product and wherein the second signal includes information about an image of the second portion taken from the second location when the product is at the second portion, wherein the first location is spaced from the second location, wherein the first portion is spaced from the second portion; wherein the data analysis module is configured to analyze the progress situation of the first work based on the time difference; and wherein the computer system is characterized to predict a progress situation of a second work based on the time difference, wherein the second work is performed from the first portion to the second portion after the first work is performed. a database configured to store modeling data; a data analysis module; and a virtual factory building module, wherein the virtual factory building module is configured to: build the virtual factory in which a progress situation of a first work performed from a first portion to a second portion is displayed, based on the modeling data and a time difference between an output time of a first signal and an output time of a second signal, which is calculated based on: the first signal output when a product is at the first portion on one or more facilities (311, 312, 313, 314, 315) monitored from a first location outside of the one or more facilities (311, 312, 313, 314, 315) used in a real factory, wherein the first signal is output from a first monitoring device configured to recognize the product and wherein the first signal includes information about an image of the first portion taken from the first location when the product is at the first portion, and the second signal output when the product is at the second portion on the one or more facilities (311, 312, 313, 314, 315) monitored from a second location outside of the one or more facilities (311, 312, 313, 314, 315), wherein the second signal is output from a second monitoring device configured to recognize the product and wherein the second signal includes information about an image of the second portion taken from the second location when the product is at the second portion, the first signal output when a product is at the first portion on one or more facilities (311, 312, 313, 314, 315) monitored from a first location outside of the one or more facilities (311, 312, 313, 314, 315) used in a real factory, wherein the first signal is output from a first monitoring device configured to recognize the product and wherein the first signal includes information about an image of the first portion taken from the first location when the product is at the first portion, and the second signal output when the product is at the second portion on the one or more facilities (311, 312, 313, 314, 315) monitored from a second location outside of the one or more facilities (311, 312, 313, 314, 315), wherein the second signal is output from a second monitoring device configured to recognize the product and wherein the second signal includes information about an image of the second portion taken from the second location when the product is at the second portion, wherein the first location is spaced from the second location, wherein the first portion is spaced from the second portion; wherein the data analysis module is configured to analyze the progress situation of the first work based on the time difference; and wherein the computer system is characterized to predict a progress situation of a second work based on the time difference, wherein the second work is performed from the first portion to the second portion after the first work is performed.