The utility model discloses a well cementing device for well of well cementation circulation instrument and branch that uses this instrument. Well cementation circulation instrument is equipped with in the instrument main part and has a perfect understanding inside and outside circulation canal including the packing element that is used for connecting the pipy instrument main part on the sleeve pipe cluster, has being used for sealing up the top of well cover annular space in the periphery of instrument main part when the distending, and circulation canal's outer port is in the below of packing element. Circulation canal can be with the interior external space of instrument main part intercommunication, and like this from slip casting pipe cluster between to well cover annular space during injected water mud, circulation canal can be followed to unnecessary grout, and to get into slip casting pipe cluster empty with the trunnion ring between the sleeve pipe cluster, and this places unnecessary grout in sleeve pipe to go here and there to avoid unnecessary grout in the aerial pressure of suppressing of the well lantern ring, make this part grout not again the bottom of sleeve pipe cluster form the cement stopper and maybe will cement the well circulation instrument top and pass the position, therefore the utility model discloses well well cementation circulation instrument has the well cementation and the reliable advantage of well cementation of the branch's well of being convenient for.