Rectangular cutting cutterhead for tunnel construction

The utility model discloses a rectangular cutting cutterhead for tunnel construction. The rectangular cutting cutterhead comprises a transmission case, a rotating shaft, a first cutterhead and a second cutterhead, the second cutterhead is connected with the first cutterhead in a matched mode through the rotating shaft, the transmission box is in driving connection with the second cutterhead, revolution can be achieved through the transmission box, and cutting pretreatment can be conducted on the area where negative cutting occurs; the first cutter head and the rotating shaft are eccentrically arranged, and the transmission box is in driving connection with the first cutter head; the first cutter head can revolve and rotate together with the rotating shaft through the transmission case; when the ratio of the revolution speed to the rotation speed of the first cutter head is 1-4 and the ratio of the radius of the first cutter head to the eccentric distance of the cutter head shaft is 7-9, the requirement of the