PROBLEM TO BE SOLVED: To provide a seedling transplanter capable of recognizing condition of seedlings to be supplied in a rear end part of a seedling tank without requiring a stoppage of planting travel when warning of reduction in an amount of seedlings is issued. SOLUTION: The seedling transplanter is composed of a riding-type traveling vehicle (2) for travelling in a field and a seedling transplantation part (4). The seedling transplantation part (4) is configured by providing: a plurality of seedling tanks (51); a planting device (52); detection members (71) for detecting the reduction in the amount of seedlings that detects seedling supply of each seedling tank (51), respectively; and a notifying member thereof, and includes: a condition sensing member (73) for sensing the supply condition of loading seedlings in the rear end side of the seedling tanks (51) and reflecting to the notifying member; a movable support mechanism (74) for movably supporting the condition sensing member (73) at the position where the condition sensing member can sense the each seedling tanks (51); and a moving control part for moving the condition sensing member (73) at the position of the seedling tank corresponding to the detected signal of the detection members (71) for detecting the reduction in the amount of seedlings by moving control of the movable support mechanism (74), for a predetermined holding time. COPYRIGHT: (C)2012,JPO&INPIT