A hopper gate opening/closing mechanism for use in a combination weigher (100) includes an actuator (31) for generating a driving force for opening and closing the hopper gate; and a cam mechanism (40A, 21) for opening and closing the hopper gate (14A) based on the driving force applied by the actuator (31); wherein the cam mechanism (40A, 21) inhibits the hopper gate (14A) from being opened in a position at which the hopper gate (14A) is closed.