A machine tool collision detecting apparatus, comprising: an emergency stop device which emergently stops a feed motor by outputting a collision detection signal (d) when an operating load (b) of a feed motor driving a movement unit reaches a collision detection setting load (c) set by a setter; and a collision stress releasing device which reversely rotates the feed motor only by a return amount set by a return amount setter (22; 22a; 22b; 22c) after the emergency stop of the feed motor, wherein the collision stress releasing device reversely rotates the feed motor only by the return amount set by the return amount setter (22; 22a; 22b; 22c) based on a contact position of a member colliding with the movement unit, wherein the machine tool collision detecting apparatus comprises: a normal load memory which sequentially updates the operating load (b) in a predetermined period during the movement of the movement unit; an intermediate load calculator which sequentially calculates an intermediate load corresponding to a load between the stored normal load and the setting load (c) by a calculation; a contact position calculator; and an auxiliary comparator which compares the operating load (b) and the intermediate load with each other and outputs an intermediate load signal when the operating load (b) reaches the intermediate load, wherein the contact position calculator calculates the contact position based on the setting load (c), the position of the movement unit when the setting load (c) is detected, the intermediate load immediately before the collision detection signal (d) is given, the position of the movement unit when the intermediate load is detected, and a value stored in the normal load memory when the collision detection signal (d) is given. an emergency stop device which emergently stops a feed motor by outputting a collision detection signal (d) when an operating load (b) of a feed motor driving a movement unit reaches a collision detection setting load (c) set by a setter; and a collision stress releasing device which reversely rotates the feed motor only by a return amount set by a return amount setter (22; 22a; 22b; 22c) after the emergency stop of the feed motor, wherein the collision stress releasing device reversely rotates the feed motor only by the return amount set by the return amount setter (22; 22a; 22b; 22c) based on a contact position of a member colliding with the movement unit, wherein the machine tool collision detecting apparatus comprises: a normal load memory which sequentially updates the operating load (b) in a predetermined period during the movement of the movement unit; an intermediate load calculator which sequentially calculates an intermediate load corresponding to a load between the stored normal load and the setting load (c) by a calculation; a contact position calculator; and an auxiliary comparator which compares the operating load (b) and the intermediate load with each other and outputs an intermediate load signal when the operating load (b) reaches the intermediate load, wherein the contact position calculator calculates the contact position based on the setting load (c), the position of the movement unit when the setting load (c) is detected, the intermediate load immediately before the collision detection signal (d) is given, the position of the movement unit when the intermediate load is detected, and a value stored in the normal load memory when the collision detection signal (d) is given. a normal load memory which sequentially updates the operating load (b) in a predetermined period during the movement of the movement unit; an intermediate load calculator which sequentially calculates an intermediate load corresponding to a load between the stored normal load and the setting load (c) by a calculation; a contact position calculator; and an auxiliary comparator which compares the operating load (b) and the intermediate load with each other and outputs an intermediate load signal when the operating load (b) reaches the intermediate load, wherein the contact position calculator calculates the contact position based on the setting load (c), the position of the movement unit when the setting load (c) is detected, the intermediate load immediately before the collision detection signal (d) is given, the position of the movement unit when the intermediate load is detected, and a value stored in the normal load memory when the collision detection signal (d) is given.