The utility model discloses a reaming device with two starters of heavy-calibre, it can not reaming success and the difficult problem of reaming centering to have solved present reaming device. Be connected through the connector (2) and the top of ream bit center pin (1) including rig drilling rod (13), the cylinder leads after from the top down has set gradually the reaming on ream bit center pin (1), as flaring bit leg (7) of flaring cutter and reaming guide to the cylinder, the diameter of the excircle profile of the lower direction rib (11) of the upper and lower direction that the reaming guide set up on to the lateral surface of reel (10) is equal with the aperture of drilling (14), the outside diameter that the upper and lower direction of on the lateral surface of reel (5) equipartition of leading after the reaming led diameter and flaring bit leg (7) of the excircle profile of rib (6) on is equal. The utility model has the advantages of creep into efficiently, the reaming centering is effectual, and the hole bottom is clear, and the ream bit wearing and tearing are little.