A power supply device comprising: a semiconductor switch element configured to: be coupled to a load through an electric wire having a thickness corresponding to a consumption current to be supplied to the load, turn on and off a power supplied to the load, wherein the semiconductor switch element comprises an output terminal configured to output a sense current (Is) corresponding to the consumption current; the power supply device further comprising: a sense resistor connected between the output terminal and ground, wherein the sense current (Is) output from the output terminal flows through the sense resistor; and a CPU comprising an A/D converter configured to perform A/D conversion on a voltage drop (Vs) generated by the sense current (Is) flowing through the sense resistor to detect the consumption current, wherein the sense resistor is provided with a variable resistance value and includes a plurality of branches connected in parallel, each of the branches comprising a resistor (Rs1 to Rs3) and a switch (S1 to S3), characterized in that: one end of each of the resistors (Rs1 to Rs3) is connected to ground, another end of each of the resistors (Rs1 to Rs3) is respectively connected to one end of a respective one of the switches (S1 to S3), and another end of each of the switches (S1 to S3) is connected to the output terminal, and the CPU is configured to read electrical wire information stored in a memory and to turn on and off the switches (S1 to S3) according to the read electric wire information, wherein the electric wire information includes information on the thickness of the electric wire, thereby setting the resistance value of the sense resistor according to the thickness of the electric wire. a semiconductor switch element configured to: be coupled to a load through an electric wire having a thickness corresponding to a consumption current to be supplied to the load, turn on and off a power supplied to the load, wherein the semiconductor switch element comprises be coupled to a load through an electric wire having a thickness corresponding to a consumption current to be supplied to the load, turn on and off a power supplied to the load, wherein the semiconductor switch element comprises an output terminal configured to output a sense current (Is) corresponding to the consumption current; the power supply device further comprising: a sense resistor connected between the output terminal and ground, wherein the sense current (Is) output from the output terminal flows through the sense resistor; and a CPU comprising an A/D converter configured to perform A/D conversion on a voltage drop (Vs) generated by the sense current (Is) flowing through the sense resistor to detect the consumption current, wherein the sense resistor is provided with a variable resistance value and includes a plurality of branches connected in parallel, each of the branches comprising a resistor (Rs1 to Rs3) and a switch (S1 to S3), characterized in that: one end of each of the resistors (Rs1 to Rs3) is connected to ground, another end of each of the resistors (Rs1 to Rs3) is respectively connected to one end of a respective one of the switches (S1 to S3), and another end of each of the switches (S1 to S3) is connected to the output terminal, and the CPU is configured to read electrical wire information stored in a memory and to turn on and off the switches (S1 to S3) according to the read electric wire information, wherein the electric wire information includes information on the thickness of the electric wire, thereby setting the resistance value of the sense resistor according to the thickness of the electric wire. a sense resistor connected between the output terminal and ground, wherein the sense current (Is) output from the output terminal flows through the sense resistor; and a CPU comprising an A/D converter configured to perform A/D conversion on a voltage drop (Vs) generated by the sense current (Is) flowing through the sense resistor to detect the consumption current, wherein the sense resistor is provided with a variable resistance value and includes a plurality of branches connected in parallel, each of the branches comprising a resistor (Rs1 to Rs3) and a switch (S1 to S3), characterized in that: one end of each of the resistors (Rs1 to Rs3) is connected to ground, another end of each of the resistors (Rs1 to Rs3) is respectively connected to one end of a respective one of the switches (S1 to S3), and another end of each of the switches (S1 to S3) is connected to the output terminal, and the CPU is configured to read electrical wire information stored in a memory and to turn on and off the switches (S1 to S3) according to the read electric wire information, wherein the electric wire information includes information on the thickness of the electric wire, thereby setting the resistance value of the sense resistor according to the thickness of the electric wire. one end of each of the resistors (Rs1 to Rs3) is connected to ground, another end of each of the resistors (Rs1 to Rs3) is respectively connected to one end of a respective one of the switches (S1 to S3), and another end of each of the switches (S1 to S3) is connected to the output terminal, and the CPU is configured to read electrical wire information stored in a memory and to turn on and off the switches (S1 to S3) according to the read electric wire information, wherein the electric wire information includes information on the thickness of the electric wire, thereby setting the resistance value of the sense resistor according to the thickness of the electric wire.