The invention discloses a dowel disassembling device. The dowel disassembling device is characterized in that the dowel disassembling device is provided with a fixed seat and a support rod, wherein connecting rods are correspondingly arranged at one end of each of the fixed seat and the support rod; a forward thread is formed on the front end part of one connecting rod, and a reverse thread is formed on the front end part of the other connecting rod; the two connecting rods are connected through a fastener which is provided with an arched bracket; nuts are arranged at the two ends of the arched bracket respectively; a positioning sleeve and a fixing nut are arranged on the support rod; a positioning threaded hole is formed in one side of the fixing sleeve; positioning grooves are formed in a positioning rod at intervals; the positioning rod penetrates through the fixing sleeve, and a positioning plate is arranged at the lower end; the positioning rod is positioned through a positioning bolt and the positioning threaded hole; a disassembling threaded rod is connected with the nut through a thread; a thimble fixture is arranged at the lower end of the disassembling threaded rod; a disassembling hole is formed in the fixed seat below a thimble which is arranged in the fixture; a rotating handle is arranged at the upper end of the disassembling threaded rod. The dowel disassembling device has the advantages of simplicity for operation, convenience for use, easiness for carrying, high working efficiency and the like.