To simplify the structure of a hopper side of a weighing apparatus, brackets 24, 34 are fitted to gates 22, 32 of pool hoppers 8 or weighing hoppers 9 and rollers 28, 38 are rotatably provided on extensions 24a, 34a thereof. On a body B side of the weighing apparatus, there are provided operating arms 44, 64 having a forked tip portion, and the rollers 28, 38 fitted to the body B side are engaged so as to be held by the operating arms 44, 64. When the operating arms 44, 64 are rocked about support shafts 43, 63, the gates 22, 32 of the hoppers 8, 9 are rocked about support shafts 25, 35 through the rollers 28, 38 to selectively open and close lower portion discharge openings 21b, 31b.