Provided is a teaching device including a grouping unit which divides machining points into machining point groups so that a machining head can sequentially machine each machining point for a machining time and so that a non-machining time can be minimized, a machining path determination unit which determines a machining path on which an in-group movement time of a robot is shortest for each machining point group, a teaching process adjustment unit which adjusts a machining order of the machining points and an operation order of the machining point groups so as to minimize a distance between groups and which optimizes the grouping so as to minimize a total movement time for completing machining, and a teaching data output unit which outputs, as teaching data, machining execution positions on the machining path obtained as a result of processing of the teaching process adjustment.