Provided is a golf swing training apparatus suited to strengthen target muscles in various body regions necessary for golf swings, and train a proper swing form. The apparatus is designed to, when a user performs a golf swing motion while grasping a grip of a golf swing mechanism whose height position is adjustable depending on a body height of a user, allow the grip to be moved along an arc, and transmit the arc movement of the grip from a swing-arm holder to a weight-arm holder to which a weight arm is fixed, through a swing-power transmission shaft, so as to swingingly move the weight arm about an axis of the weight-arm holder to allow a weight member on the weight arm to act as a load countering golf swing power. The apparatus has a mechanism capable of allowing the load based on the weight member fastened to the weight arm to be arbitrarily adjusted depending on individual differences in muscle strength.