To provide a seed potato planter which can perform local fertilization dropping fertilizers such as a fertilizer, chemicals and the like only near the seed potato to be planted.

A seed potato planter A is composed to orbitally run an endless transfer belt 14 synchronized with running of a machine body 18, so that seed potatoes K mounted on each of transfer plates 15 attached on the transfer belt 14 at constant spaced intervals are transferred to the dropping part at the lower end of the reverse-directionally running part of the transfer belt 14, and are dropped one by one and planted by an operator U, wherein a seed potato dropping detecting device B detecting one by one the seed potato K dropped from the dropping part and a fertilizer-chemical applying device D for dropping the fertilizer and/or the chemicals by a predetermined amount near the seed potato K dropped at the planting part of the farm, synchronously operating with the detection of the seed potato K by the seed potato dropping detecting device B, are equipped.