In Japan, nose rings are still widely used in beef cattle; however, the stress responses caused by the pain of nose ring placement have been rarely studied. This study investigates whether stress responses during nose ring placement differ depending on two developmental stages of the beef cattle. Japanese Black calves (2-4 months age) and yearling (12-14 months age) were used. Cattle in both developmental stages were divided into a nose ring treatment group and a control group. Blood samples and electrocardiograms were collected, and behavioural changes were observed at six time points: before nose ring placement (0 min), after nose ring placement (5 min), and at 15-, 30-, 60-, and 120-min post-placement. Stress responses were evaluated by analyzing differences in cortisol concentration, heart rate (HR), heart rate variability (HRV), and the frequency of nasal licking behaviour (LIC) between the treatment and control groups. The results indicated that stress responses were observed at 5 min after nose ring placement, as evidenced by significant increases in cortisol levels, HR, and nasal licking behaviour (p < 0.05) in both developmental stages. However, no significant differences in HR and LIC were observed between the two developmental stages, and both returned to baseline levels within 15 min. In contrast, cortisol responses varied with developmental stage. In the yearling group, cortisol levels exhibited a greater increase and required a longer time (30 min) to return to baseline compared to the calf group, in which cortisol levels returned to baseline within 15 min. These findings suggest that stress responses induced by the pain of nose ring placement vary by developmental stage, with younger cattle experiencing shorter-lasting stress responses. Notably, the stress responses in both developmental stages resolved within 30 min, indicating that nose ring placement does not cause the prolonged and intense pain or stress responses associated with procedures such as castration or dehorning.