Background: Prompt detection and treatment of high-grade cervical intraepithelial neoplasia (CIN), namely, CIN3, are important for preventing malignant transformation. In most cases, such treatment is performed through conization, but minimally invasive procedures must also be considered. Therefore, we present a surgical method using a combination of monopolar electrosurgical conization (MESC) and oxidized regenerated cellulose-based haemostat (ORCH) (Surgicel®) and discuss its merits and risk factors. Methods: The medical records of 274 patients treated at our hospital from January 1, 2015, to December 31, 2021, were retrospectively reviewed. To detect risk factors for postoperative problems, we considered 2 indicators: postoperative recurrence and haemostatic suture for severe postoperative bleeding. We also focused on the following 10 representative factors for predicting significant risk for postoperative problems: (1) advanced age, (2) high BMI, (3) nulliparity, (4) smoking history, (5) long operation time, (6) intraoperative suture, (7) positive margin, (8) invasive squamous cell carcinoma (SCC), (9) no dysplasia, and (10) cervical glandular neoplasia (CGN). Results: Among the 274 patients, 19 instances of postoperative recurrence and 8 instances of haemostatic suture were detected. In a multivariate analysis of the 10 factors, we detected no significant impact except for “no dysplasia” on both indicators. This result indicated that our method had no specific risk and could provide a certain extent of usability. Conclusions: The combination of MESC and ORCH for the treatment of CIN3 could be performed effectively and safely with minimal intraoperative haemostatic suturing of the cut surface.