The invention relates to a pit digging volume detection device for roadbed compaction degree detection. The pit digging volume detection device comprises one or two measuring units, wherein each measuring unit comprises a measuring unit housing; each measuring unit housing is provided with a liquid storage piston cavity for filling liquid; a liquid pressing piston in contact with the liquid is movably assembled in each liquid storage piston cavity in a sealing manner; an elastic film of which the inner side is communicated with the corresponding liquid storage piston cavity and the outer sideis used for fully paving corresponding parts of a roadbed is fixed on each measuring unit housing. According to the pit digging volume detection device, the technical problem of high labor intensity caused by the fact that sand needs to be manually taken out when the pit digging volume is obtained by sand filling in the prior art is solved.