To provide an underground continuous wall execution work support system for performing optimal excavation work by providing information required in accordance with a ground state.

A control server 26 is connected to an excavator 10 of respective job sites via a network, and is provided with a ground strength evaluating part for determining the ground strength distribution of the excavation object ground in the depth direction on the basis of imparted ground properties, a required excavation capacity operation part for determining required excavation capacity of a cutter post balancing with excavation resistance force obtained from cumulative ground strength by determining the cumulative ground strength from the ground strength distribution, a comparing part for comparing the determined required excavation capacity with excavation capacity of the excavator 10 carried in the job site, an excavation efficiency evaluating part for evaluating excavation efficiency on the basis of the compared result, and a transmitter-receiver for transmitting and receiving an evaluation result of the excavation efficiency to the excavator 10 by receiving a request from the excavator 10.