A security system of a construction machine of the present invention has a construction machine, a base station and a communication device. The construction machine comprises a data sending and receiving portion for sending first information, a storage portion for storing received information, and a control portion for controlling an operation of the construction machine. The base station receives the first information from the data sending and receiving portion of the construction machine and sends second information to the construction machine and manages the construction machine. It is configured so that the communication device is connected to the base station through a communication network and can send third information to the construction machine through the base station.