Marking line device suitable for scar development after breast cancer operation

The invention discloses a breast cancer postoperative scar developing marking line device which comprises a box body, two first shaft parts, an auxiliary bonding piece and a cutting knife, the two first shaft parts are provided with a dry cotton thread roll and an adhesive tape roll respectively, and a contrast agent is injected into an inner cavity of the box body; the two first shaft parts, the dry cotton thread roll, the adhesive tape roll and the auxiliary bonding piece are all located on the outer top face of the box body, the two first shaft parts are fixed to the box body, a thread inlet hole and a thread outlet hole which are communicated with an inner cavity of the box body are formed in the positions, between the dry cotton thread roll and the adhesive tape roll, of the top face of the box body, and the inner cavity of the box body is further provided with a second shaft part perpendicular to the two first shaft parts. One end of a cotton thread of the dry cotton thread roll extends into the contras