Provided is an information sharing system which allows setting information relating to a second communication device to be shared with a first communication device. The information sharing system includes an information collection device that retains the setting information and is communicatively connected to the first communication device, and a management device that makes a request for transmission of the setting information with respect to the information collection device. The management device includes a communication management unit that determines whether or not communication is established between the first and second communication devices when receiving the request for transmission of the setting information, and an information request unit that makes a request for transmission of the setting information with respect to the information collection device in a case where it is determined by the communication management unit that the communication is established between the first and second communication devices. The information collection device includes an information management unit that transmits the setting information to the first communication device in response to the request made by the information request unit.