A gas flow channel forming body for a fuel cell, comprising: a partition wall having a first surface and a second surface opposite to the first surface; a plurality of protrusions (34, 134) provided in parallel on the first surface; a gas flow channel (32, 132) provided between adjacent two of the protrusions (34, 134); a plurality of water introduction channels (33, 133) on the second surface, wherein each water introduction passage is provided in a valley positioned opposite to one of the protrusions; and a plurality of communication channels (36, 136), each of which is provided in the partition wall to allow the gas flow channel (32, 132) to communicate with the water introduction channel (33, 133) and water to pass therebetween; characterized in that the gas flow channel forming body comprises: a plurality of intermediate structure bodies (39, 139), each of which is provided in one of the water introduction channels (33, 133) to be opposed to one of the communication channels (36, 136), wherein a set of communication channels (36, 136) is formed by at least a pair of the communication channels (36, 136) arranged at a first interval, the set of communication channels (36, 136) and an adjacent set of communication channels (36, 136) are arranged at a second interval in each protrusion (34, 134), the communication channels (36, 136) are formed by a slit in which capillary action works, a gap (39, 139a) between the intermediate structure bodies (39, 139) communicates with the communication channel (26, 136), and the second interval is larger than the first interval. a partition wall having a first surface and a second surface opposite to the first surface; a plurality of protrusions (34, 134) provided in parallel on the first surface; a gas flow channel (32, 132) provided between adjacent two of the protrusions (34, 134); a plurality of water introduction channels (33, 133) on the second surface, wherein each water introduction passage is provided in a valley positioned opposite to one of the protrusions; and a plurality of communication channels (36, 136), each of which is provided in the partition wall to allow the gas flow channel (32, 132) to communicate with the water introduction channel (33, 133) and water to pass therebetween; characterized in that the gas flow channel forming body comprises: a plurality of intermediate structure bodies (39, 139), each of which is provided in one of the water introduction channels (33, 133) to be opposed to one of the communication channels (36, 136), wherein a set of communication channels (36, 136) is formed by at least a pair of the communication channels (36, 136) arranged at a first interval, the set of communication channels (36, 136) and an adjacent set of communication channels (36, 136) are arranged at a second interval in each protrusion (34, 134), the communication channels (36, 136) are formed by a slit in which capillary action works, a gap (39, 139a) between the intermediate structure bodies (39, 139) communicates with the communication channel (26, 136), and the second interval is larger than the first interval. a plurality of intermediate structure bodies (39, 139), each of which is provided in one of the water introduction channels (33, 133) to be opposed to one of the communication channels (36, 136), wherein a set of communication channels (36, 136) is formed by at least a pair of the communication channels (36, 136) arranged at a first interval, the set of communication channels (36, 136) and an adjacent set of communication channels (36, 136) are arranged at a second interval in each protrusion (34, 134), the communication channels (36, 136) are formed by a slit in which capillary action works, a gap (39, 139a) between the intermediate structure bodies (39, 139) communicates with the communication channel (26, 136), and the second interval is larger than the first interval.