An electric power tool comprising: a tool main body; an induction motor configured to generate a power of the electric power tool, wherein the induction motor includes at least one phase winding; and an inverter configured to receive supply of a drive voltage from a power supply unit and drive the induction motor, characterised in that the power supply unit is configured to rectify an alternating-current voltage supplied from an external alternating-current power source and generate the drive voltage for driving the induction motor wherein the power supply unit and the inverter are integrally incorporated in the tool main body together with the induction motor; and wherein the power supply unit includes a rectifier circuit (36, 37, 38, 39) configured to perform full-wave rectification of the alternating-current voltage and output a full-wave rectified voltage as an output voltage, wherein the inverter includes: a switching circuit having a plurality of switching elements (Q1, Q2, Q3, Q4, Q5, Q6) configured to apply the output voltage outputted from the rectifier circuit (36, 37, 38, 39) to the at least one phase winding of the induction motor; and a control unit configured to perform a drive control of each of the plurality of switching elements (Q1, Q2, Q3, Q4, Q5, Q6) so that a rotation speed of the induction motor becomes a predetermined speed, wherein the control unit includes: a drive frequency calculation unit configured to set a drive frequency of the induction motor, based on a rotation speed of the induction motor and a slip frequency of the induction motor; a drive unit configured to drive each of the plurality of switching elements (Q1, Q2, Q3, Q4, Q5, Q6) depending on the drive frequency set by the drive frequency calculation unit; and a slip frequency setting unit (74, 76) configured to set the slip frequency depending on a change in the drive voltage generated in the power supply unit. a tool main body; an induction motor configured to generate a power of the electric power tool, wherein the induction motor includes at least one phase winding; and an inverter configured to receive supply of a drive voltage from a power supply unit and drive the induction motor, characterised in that the power supply unit is configured to rectify an alternating-current voltage supplied from an external alternating-current power source and generate the drive voltage for driving the induction motor wherein the power supply unit and the inverter are integrally incorporated in the tool main body together with the induction motor; and a switching circuit having a plurality of switching elements (Q1, Q2, Q3, Q4, Q5, Q6) configured to apply the output voltage outputted from the rectifier circuit (36, 37, 38, 39) to the at least one phase winding of the induction motor; and a control unit configured to perform a drive control of each of the plurality of switching elements (Q1, Q2, Q3, Q4, Q5, Q6) so that a rotation speed of the induction motor becomes a predetermined speed, a drive frequency calculation unit configured to set a drive frequency of the induction motor, based on a rotation speed of the induction motor and a slip frequency of the induction motor; a drive unit configured to drive each of the plurality of switching elements (Q1, Q2, Q3, Q4, Q5, Q6) depending on the drive frequency set by the drive frequency calculation unit; and a slip frequency setting unit (74, 76) configured to set the slip frequency depending on a change in the drive voltage generated in the power supply unit.