In a hybrid transmission, a two-degree of freedom differential unit includes four or more rotary members and is structured in such a way that, when revolution states of two rotary members from among the four or more rotary members are determined, the revolution states of the other rotary members are determined, sequentially couples the respective rotary members, in a higher revolution speed order, to one motor/generator, to one of an output to a drive system and an input from a main power source, to the other of the output and input, and to another motor/generator, and a brake is installed to fix one of the rotary members related to the input.