An injection molding machine , comprising: a motor ; a driver circuit (51, 52, 53,5 54) that drives the motor characterized by a rectifying part that supplies electric power to the driver circuit ; a regenerative line of regenerative electric power of the motor connected to the rectifying part in parallel; a converting part and a harmonics component reducing part provided in the regenerative line , the converting part converting direct electric power between the driver circuit and the rectifying part into alternating electric power which is input to the harmonics component reducing part ; and a controlling part that is configured to control an operation of the converting part , wherein the controlling part is configured to control a regenerative operation of the converting part according to a direct voltage between the driver circuit and the rectifying part , wherein the controlling part is configured to perform a PWM control of the converting part based on the direct voltage between the driver circuit and the rectifying part , an alternating voltage between the converting part and the harmonics component reducing part , and an alternating voltage at an output side of the harmonics component reducing part ; and wherein the controlling part is configured to determine that a regeneration stop criterion is met and to stop regenerating operation of the converting part when a direct voltage value between the driver circuit and the rectifying part is smaller than a predetermined voltage value (Vth) and a peak value of an alternative current between the converting part and the harmonics component reducing part is smaller than a predetermined current value. a motor ; a driver circuit (51, 52, 53,5 54) that drives the motor characterized by a rectifying part that supplies electric power to the driver circuit ; a regenerative line of regenerative electric power of the motor connected to the rectifying part in parallel; a converting part and a harmonics component reducing part provided in the regenerative line , the converting part converting direct electric power between the driver circuit and the rectifying part into alternating electric power which is input to the harmonics component reducing part ; and a controlling part that is configured to control an operation of the converting part , wherein the controlling part is configured to control a regenerative operation of the converting part according to a direct voltage between the driver circuit and the rectifying part , wherein the controlling part is configured to perform a PWM control of the converting part based on the direct voltage between the driver circuit and the rectifying part , an alternating voltage between the converting part and the harmonics component reducing part , and an alternating voltage at an output side of the harmonics component reducing part ; and wherein the controlling part is configured to determine that a regeneration stop criterion is met and to stop regenerating operation of the converting part when a direct voltage value between the driver circuit and the rectifying part is smaller than a predetermined voltage value (Vth) and a peak value of an alternative current between the converting part and the harmonics component reducing part is smaller than a predetermined current value. <EOS>