Network analysis device, management system, network analysis method and program

In the present invention, a message information collection unit (102) collects packets transmitted over a building management system network (11) as well as analysis results thereof as first message information. A storage unit (104) stores the first message information which has been collected at the message information collection unit (102). A message information collection unit (103) collects packets transmitted over a facilities network (12) as well as analysis results thereof as second message information. A storage unit (105) stores the second message information which has been collected at the message information collection unit (103). A message association unit (106) associates the first message information which has been stored at the storage unit (104) with the second message information which has been stored at the storage unit (105). A display unit (107) displays analysis results of the association at the message association unit (106).