A lie-down massager comprises a frame having an elongated top panel with an elongated opening, a rider below the top panel, a guide member movably engaged between the frame and the rider to enable the rider to make a horizontal reciprocation relative to the frame, a lifter moving vertically relative to the rider, and a roller gear engaged to the rider. The roller gear is engaged to a vertical rack gear in an opening of an engagement body extending from the lifter so the roller gear rotation enables the lifter to make a vertical reciprocation. Massage bumps attached to the top portion of the lifter move vertically and/or horizontally along the elongated top opening of the elongated top panel of the frame by the lifter and the rider.