PURPOSE: To carry out proper completion treatment of milking according to bovine body characteristics by releasing teat cup liners when the rate of decrease exceeds the reference rate in decreasing the flow rate of milk in milking and raising an alarm when the rate of decrease is below the reference rate.

CONSTITUTION: A milk pipe 51 is connected through a controller 20 to a milk craw 54 and then through teat cup liners (Ca), (Cb), (Cc) and (Cd) to a vacuum pipe 52. The flow rate value of milk in milking is obtained with a flow rate detecting circuit. The teat cup liners are released with a cylinder 56 when the rate of decrease in decreasing the flow rate exceeds the reference rate. When the rate of decrease is below the reference rate, an alarm is raised.