An information search system includes a terminal device and a communicator. The terminal device includes an obtainer, a processor, and a communicator. The obtainer obtains device specification information which is necessary for specifying a device installed in a plant. The processor obtains first information and second information. The first information is identification information of the device specified by using the device specification information. The second information represents a storage place of information which is necessary for maintaining the device. The communicator transmits the first information and the second information to a network. The, search server specifies a search place based on the second information transmitted from the terminal device through the network. The search server searches the search place by using the first information as a key. The search server transmits a search result to the terminal device.