A contents deletion/update system includes plural nodes which delete or update contents shared by the plural nodes mutually connected via a network. A management node includes a first transmitter transmitting an instruction to cause another node to delete or update the contents based on owning node information, and a second transmitter transmitting non-responding node information when there is a non-responding node. Each of the other nodes includes the first receiver receiving an instruction to delete or update the contents, an editor deleting or updating the contents according to the instruction, the first transmitter transmitting a response to the management node, the second receiver receiving non-responding node information from the management node and storing the non-responding node information in a storage unit, and the second transmitter transmitting the instruction to the non-responding node based on the non-responding node information when recognizing that the non-responding node makes access.