There is provided a DC/DC converter that can eliminate the necessity of current sense resistors to thereby reduce the mounting area, improve the efficiency, and realize favorable transient characteristics. A multi-phase DC/DC converter with N phases (N is an integer equal to or greater than 2) is provided. A high-side transistor MH, a low-side transistor ML, and an inductor L are provided for each phase φ. Output power supply wiring connects a load side end of each of N inductors L1 to LN and a load. The output power supply wiring is branched from the load toward the load side ends of the N inductors L1 to LN. A coil current flowing through an inductor Li of an ith phase φi (i=1, 2, . . . N) is detected based on a voltage drop Vsi of a branch portion bri corresponding to the phase φi of the output power supply wiring.