A lubricating oil supply device for an automatic transmission that includes a washer arranged inside the automatic transmission and regulating a movement of an input shaft in the automatic transmission in a shaft direction, wherein the washer includes: an oil reception section that receives lubricating oil scattered by a centrifugal force in a radial direction of the input shaft of the automatic transmission, and a guide path that guides the lubricating oil received by the oil reception section to a thrust surface at an end surface of the washer in the shaft direction.