A motor control device having a function of detecting a rotating rotor position of a synchronous motor in a sensor-less manner, comprising: current detecting means for detecting a current flowing through a coil (Uc, Vc, WC) of the synchronous motor; voltage detecting means for detecting a voltage applied to the coil (Uc, Vc, WC) of the synchronous motor; Ip and θi detecting means for detecting a current peak value Ip and a current electrical angle θi based on the current detected by the current detecting means; Ep and θe detecting means for detecting an induced voltage peak value Ep and an induced voltage electrical angle θe based on the current detected by the current detecting means and the voltage detected by the voltage detecting means; phase storing means for previously storing a current phase β or an induced voltage phase γ defined by at least two parameters selected from a value of Ip, a value of Ep, and a subtracted value (θe-θi) obtained by subtracting θi from θe; phase selecting means for selecting β or γ based on Ip and θi detected by the Ip and θi detecting means and Ep and θe detected by the Ep and θe detecting means by making reference to β or γ stored in the phase storing means; and rotor position calculating means for calculating a rotor position θm from a rotor position computational expression using β selected by the phase selecting means as a first variable and using θi detected by the Ip and θi detecting means as a second variable or a rotor computational expression using γ selected by the phase selecting means as a first variable and using θe detected by the Ep and θe detecting means as a second variable, characterized in that the motor control device further comprises: correcting means for correcting at least one of Ep and θe, which are detected by the Ep and θe detecting means and included in the at least two parameters that defined β or γ, according to a change in current flowing through the coil (Uc, Vc, WC) at the time of selecting β or γ by the phase selecting means. current detecting means for detecting a current flowing through a coil (Uc, Vc, WC) of the synchronous motor; voltage detecting means for detecting a voltage applied to the coil (Uc, Vc, WC) of the synchronous motor; Ip and θi detecting means for detecting a current peak value Ip and a current electrical angle θi based on the current detected by the current detecting means; Ep and θe detecting means for detecting an induced voltage peak value Ep and an induced voltage electrical angle θe based on the current detected by the current detecting means and the voltage detected by the voltage detecting means; phase storing means for previously storing a current phase β or an induced voltage phase γ defined by at least two parameters selected from a value of Ip, a value of Ep, and a subtracted value (θe-θi) obtained by subtracting θi from θe; phase selecting means for selecting β or γ based on Ip and θi detected by the Ip and θi detecting means and Ep and θe detected by the Ep and θe detecting means by making reference to β or γ stored in the phase storing means; and rotor position calculating means for calculating a rotor position θm from a rotor position computational expression using β selected by the phase selecting means as a first variable and using θi detected by the Ip and θi detecting means as a second variable or a rotor computational expression using γ selected by the phase selecting means as a first variable and using θe detected by the Ep and θe detecting means as a second variable, characterized in that the motor control device further comprises: correcting means for correcting at least one of Ep and θe, which are detected by the Ep and θe detecting means and included in the at least two parameters that defined β or γ, according to a change in current flowing through the coil (Uc, Vc, WC) at the time of selecting β or γ by the phase selecting means. correcting means for correcting at least one of Ep and θe, which are detected by the Ep and θe detecting means and included in the at least two parameters that defined β or γ, according to a change in current flowing through the coil (Uc, Vc, WC) at the time of selecting β or γ by the phase selecting means.