Disclosed are a work machine and a communication monitoring method that allow recording of work information even in the event of interruption of communication in a communication path between the work machine, a mobile communication terminal and a server. There is provided a control section (71) configured to transmit work information to a server (Z) via a communication section (68) and a smartphone (Y) if a monitoring section (69) detects that communication is possible between the communication section (68) and the smartphone (Y) and also to cause a storage section (70) to store the work information if the monitoring section (69) detects that communication is not possible between the communication section (68) and the smartphone (Y).