A vehicle power transmission device having a torque converter in a power transmission path between an engine and drive wheels, the torque converter including an input-side rotating member disposed with a plurality of pump blades, an output-side rotating member disposed with a plurality of turbine blades receiving a fluid flow from the pump blades, and a stator disposed with a stator blade disposed between the pump blades and the turbine blades, the vehicle power transmission device having: a one way clutch being disposed between the stator and a non-rotating member which supports the stator; and a case including a first chamber and a second chamber separated by a bulkhead disposed on an opposite side of the torque converter to the engine, the first chamber housing the torque converter, the second chamber being formed on an opposite side of the bulkhead to the torque converter, the first chamber and the second chamber being oil-tightly isolated from each other by an oil seal oil-tightly sealing a gap between an inner circumferential surface of the bulkhead and an outer circumferential surface of a cylindrical rotation shaft projected from the input-side rotating member toward the second chamber, characterized in that the vehicle power transmission device is disposed with a thrust bearing between a side wall portion of the input-side rotating member closer to the bulkhead and the stator, the thrust bearing is disposed to partially or entirely overlap with the oil seal when viewed in a direction orthogonal to an axial center of the torque converter, a portion of the one way clutch protrudes toward the second chamber as compared to the stator and an inner race of the one way clutch, the input-side rotating member has an annular projecting portion formed by projecting a portion at a radial position corresponding to the thrust bearing toward the bulkhead over entire circumference in the side wall portion of the input-side rotating member closer to the bulkhead, and the annular projecting portion contains the thrust bearing and a portion of the one way clutch. a one way clutch being disposed between the stator and a non-rotating member which supports the stator; and a case including a first chamber and a second chamber separated by a bulkhead disposed on an opposite side of the torque converter to the engine, the first chamber housing the torque converter, the second chamber being formed on an opposite side of the bulkhead to the torque converter, the first chamber and the second chamber being oil-tightly isolated from each other by an oil seal oil-tightly sealing a gap between an inner circumferential surface of the bulkhead and an outer circumferential surface of a cylindrical rotation shaft projected from the input-side rotating member toward the second chamber, characterized in that the vehicle power transmission device is disposed with a thrust bearing between a side wall portion of the input-side rotating member closer to the bulkhead and the stator, the thrust bearing is disposed to partially or entirely overlap with the oil seal when viewed in a direction orthogonal to an axial center of the torque converter, a portion of the one way clutch protrudes toward the second chamber as compared to the stator and an inner race of the one way clutch, the input-side rotating member has an annular projecting portion formed by projecting a portion at a radial position corresponding to the thrust bearing toward the bulkhead over entire circumference in the side wall portion of the input-side rotating member closer to the bulkhead, and the annular projecting portion contains the thrust bearing and a portion of the one way clutch.