A multiphase electric motor control device includes: a bridge circuit including phase circuits each including a high potential side switching element, a low potential side switching element, and a current detector, a PWM control unit that outputs PWM signals to the switching elements; a control unit that acquires phase current values at a timing synchronized with a triangle wave; and a current value estimation unit that estimates a phase current value of one phase based on phase current values of other phases. In a case where an ON time of the PWM signal output to the low potential side switching element of the one phase from the PWM control unit is shorter than a predetermined time, the control unit acquires the phase current values which are detected by shifting the timing by using the current detectors of at least the other phases.