Construction engineering cost preliminary calculation rehearsal device

The invention discloses a construction engineering cost preliminary calculation rehearsal device. A shell is included. Containing cavities are formed in the front end and the rear end of the shell. The corresponding positions in the upper ends of the containing cavities are provided with transverse holes. Casing pipes are placed in the two containing cavities. The two ends of writing paper are wound around the two casing pipes correspondingly. The writing paper penetrates through the two transverse holes. A left fixing plate is arranged at the left end of the shell. A right fixing plate is fixed to the right side of the shell. The left ends of the two casing pipes are coaxially fixedly provided with rotation rods. The right ends of the two rotation rods penetrate through and extend to theleft side of the left fixing plate. An elastic arc plate is fixed to the outer side of the right fixing plate. When data are fully written on the exposed writing paper, a user rotates one rotation block, the rotation block dr