A power transmission apparatus T of a four wheel drive vehicle is provided with a multiple disc clutch C engaged in accordance with a difference between rotational speeds of a front wheel Wf and a rear wheel Wr and a gear ratio of a second gear mechanism 5 for transmitting rotation of the rear wheel Wr to an output shaft 9 of the multiple disc clutch C is set to be larger than a gear ratio of a first gear mechanism 4 for transmitting rotation of the front wheel Wf to an input shaft 8 of the multiple disc clutch C.