A dynamic resource allocation apparatus and method for assigning timeslot in a return channel in multi-frequency time division multiple access MF-TDMA in order to have a maximum throughput is disclosed. The apparatus includes: resource request amount collection unit for accumulating a requested resource amount corresponding to each of terminals during a super-frame period; resource request amount processing unit for dividing an accumulated requested resource amount by the number of frame pairs in a super frame and storing a sum of a result of dividing and rounding up a remain of the division to a nearest integer as a request amount of each corresponding terminal; and resource allocation unit for deciding a time slot allocated at each of terminals corresponding to a frame pair based on optimal allocation amount, which is decided based on the request amount by the requested amount processing unit.