Transcutaneous electrical sensory stimulation (TESS) devices are approved for use in Japan, but their safety when used through the neck skin for dysphagia rehabilitation has not been reported. This study aimed to verify the safety of TESS use through the neck skin. Twenty patients (mean age 86.5 ± 5.1 years) with aspiration pneumonia undergoing dysphagia rehabilitation were included in this retrospective observational and matched control study. We compared vital signs in 10 subjects who underwent swallowing rehabilitation with the TESS device, and matched control patients over 7 days. The results were the following: tachycardia, 0.60 ± 1.07 vs. 0.70 ± 0.67 days; high blood pressure, 0.40 ± 0.70 vs. 0.50 ± 1.08 days; low blood pressure, 0.40 ± 0.70 vs. 0.10 ± 0.32 days; low oxygen saturation, 0.60 ± 1.58 vs. 0.50 ± 1.08 days, p = 0.870; oxygen administration, 0.80 ± 2.20 vs. 1.20 ± 2.15 days; tachypnea, 0.50 ± 0.71 vs. 0.50 ± 0.53 days; elevated body temperature, 2.00 ± 1.41 vs. 1.60 ± 1.96 days. There were no significant differences in clinical stability between the TESS and control groups of patients with aspiration pneumonia. TESS through the neck appears safe as an intervention in dysphagia rehabilitation.