In a transmission, a lubrication oil retention section is formed to surround an area around a circumferential part of a first gear that ranges from a lubrication oil storage region to the outside of the lubrication oil storage region. In the lubrication oil retention section, the lubrication oil scooped up by the rotation of the first gear is retained between the lubrication oil retention section and the first gear at the outside of the lubrication oil storage region. The lubrication oil retention section enables the first gear to splash the lubrication oil retained at the outside of the lubrication oil storage region, toward a receiver that flows the lubrication oil to various sliding parts of the transmission.