A utilized service management system for managing an external service that is utilized when a user website provided by a user server is accessed, the system comprising: a Content Security Policy, CSP, tag generation unit for generating a CSP tag comprising a tag of content security policy that allows access to only a prescribed domain and is defined by the World Wide Web Consortium, wherein the CSP tag generation unit is installed in a utilized service management server different from the user server, comprises a reception unit for receiving, from a user who manages the user server, an external service desired to be blocked, and is configured to generate content security policy to inhibit access to a domain of the external service desired to be blocked that is received by the reception unit, the system further comprising: an external request extraction unit that accesses the user website and extracts an URL providing access to a domain other than that of the user website; an external service database storing a domain, a path and a service name of each external service that are associated with each other; and a utilized service identification unit that refers to the external service database and identifies a service name corresponding to a domain and a path of the URL extracted by the external request extraction unit, wherein the reception unit is configured to provide a management web page on which external services to be blocked or allowed can be selected from a list of the service names identified by the utilized service identification unit. a Content Security Policy, CSP, tag generation unit for generating a CSP tag comprising a tag of content security policy that allows access to only a prescribed domain and is defined by the World Wide Web Consortium, wherein the CSP tag generation unit is installed in a utilized service management server different from the user server, comprises a reception unit for receiving, from a user who manages the user server, an external service desired to be blocked, and is configured to generate content security policy to inhibit access to a domain of the external service desired to be blocked that is received by the reception unit, the system further comprising: an external request extraction unit that accesses the user website and extracts an URL providing access to a domain other than that of the user website; an external service database storing a domain, a path and a service name of each external service that are associated with each other; and a utilized service identification unit that refers to the external service database and identifies a service name corresponding to a domain and a path of the URL extracted by the external request extraction unit, wherein the reception unit is configured to provide a management web page on which external services to be blocked or allowed can be selected from a list of the service names identified by the utilized service identification unit. an external request extraction unit that accesses the user website and extracts an URL providing access to a domain other than that of the user website; an external service database storing a domain, a path and a service name of each external service that are associated with each other; and a utilized service identification unit that refers to the external service database and identifies a service name corresponding to a domain and a path of the URL extracted by the external request extraction unit, wherein the reception unit is configured to provide a management web page on which external services to be blocked or allowed can be selected from a list of the service names identified by the utilized service identification unit.