Abstract: A master communication apparatus uses a band control device comprising a band weight holding section storing weight proportional to minimum assured speed based on a slave communication apparatus, an assignment number-of-times counter for counting, based on a constant packet size, a length of a packet transmitted by the slave communication apparatus, a transmission sequence control section for giving transmission permissions in a sequence, based on a constant packet size, to the slave communication apparatuses and suspending the transmission permission in a sequence that the assignment number-of-times counter exceeds a band weight amount corresponding to the slave apparatus, thereby assuring a minimum speed based on the slave communication apparatus and reducing the variation in data transmission wait time.