An oil supplying device for a vehicle transmission is to improve cooling property of a lubricated part. Therefore, an input shaft, an output gear, an intermediate shaft and a transmission shaft with a tain end transmission gear are placed in a transmission housing. In the oil supplying device, in which an oil groove is disposed and oil scrapped by the tail end transmission gear is guided to the lubricated part; the oil groove is provided with an oil inlet channel part and an oil storage channel part; an oil supplying guide part is arranged over a contact part between the output gear and the intermediate gear in the transmission housing, and on a tangent line of the output gear and the intermediate gear; the oil supplying guide part is provided with an inlet facing the contact part, a guide part extending toward the upper side of the tangenet line from the inlet, and a cover part projecting from the upper end of the guide part to a place over the oil storage channel.