Claim 1 in question reads as follows: 特許第3166151号. A drip bag, comprising a bag main body made of a water-permeable filtering sheet material and having an opening part in an upper end portion thereof; and hook members each made of a thin plate-like material and disposed on two opposite outside surfaces of the bag main body, respectively, each of said hook members having a peripheral portion formed at a periphery of said hook member, an arm portion formed inside said peripheral portion so that said arm portion can be pulled up from said bag main body, and a tongue piece portion formed inside said peripheral portion, said peripheral and said arm portions being continuous with each other at one of upper and lower ends of said arm portion, said arm and said tongue piece portions being continuous with each other at the other of said upper and lower ends of said arm portion, said peripheral portion or said tongue piece portion being bonded on said outside surface of said bag main body.