The hinotori™ Surgical Robot System (hinotori™, Medicaroid, Kobe, Japan) is increasingly being utilized primarily in urology and adult surgery; however, data on its application in pediatric surgery are lacking. This preclinical study aimed to evaluate the limitations of this system for accurate suturing in small cavities, designed for pediatric and neonatal applications. Two trained operators performed simple ligature sutures (easy task [ET]) and hepaticojejunostomy sutures (difficult task [DT]) within five differently sized boxes, ranging from 5123 mL to 125 mL. The suture time, number of internal and external instrument/instrument collisions, instrument/box collisions, and suture accuracy were evaluated. The suture accuracy was assessed using the A-Lap Mini endoscopic surgery skill assessment system. As a result, an increase in the number of collisions and extended suturing times were observed in boxes with volumes smaller than 215 mL. Despite these variations, there were no significant differences between the boxes, and all tasks were precisely performed in all boxes (p = 0.10 for the ET and 1.00 for the DT). These findings demonstrate the capability of the hinotori™ system to perform precise suturing techniques within tightly confined simulated neonatal cavities as small as 125 mL. To advance the integration of pediatric robotic surgery utilizing the hinotori™ system, additional trials comparing it with conventional laparoscopic and thoracoscopic techniques using pediatric and animal models are necessary, to assess its clinical safety and applicability.