Generally, the calcium salts of fatty acids affect feed intake, however, it is unclear whether these affect feeding behavior including concentrate provision and voluntary visits in an automatic milking system (AMS). This study investigated whether supplementation of calcium salts of medium-chain fatty acids (MCFA) modified the feeding behavior and milking activity in an AMS. Six multiparous Holstein cows (initial days in milk, 202; initial BW, 707 kg; parity, 2.3) in a cow herd kept in a free cow traffic barn with AMS and the roughage intake control (RIC) system were used in a replicated 3 × 3 Latin square design with 21-d periods. Cows were fed a partly mixed ration (PMR) supplemented with MCFA. MCFA composed of 80% capric acid and 20% caprylic acid was added to PMR at 0%, 0.5%, or 1.0% of the total dry matter intake. All cows received the same PMR (EE, 3.3%; NDF, 44.3%) ad libitum. A concentrate diet (EE; 3.5%) was offered at the AMS in proportion to individual milk yield. Data of milking activity and ruminating time were collected from the AMS system. Feeding behavior was analyzed using the records by the RIC system. The meal was determined by a log survivor curve for intervals between feedings for each cow. Data were analyzed by ANOVA to determine effects of MCFA. Correlation coefficients (r) were determined between feeding behavior and milking activity. The MCFA did not affect milking activity and feeding behavior. However, ruminating time was found to be positively correlated (P < 0.01) with milk yield and daily milking frequency (r = 0.77 and r = 0.64, respectively). An increased daily milking frequency was associated (P < 0.05) with longer meal duration and decreased visiting frequency to the feed box with RIC system (r = 0.58 and r = −0.49, respectively). In conclusion, these results indicated that bovine behavior of cows in AMS was not affected by the MCFA, and individual difference in feeding behavior among cows could relate to individual variation of milking activity.