A voltage-current conversion circuit configured to convert a voltage at a first voltage input terminal to a current and output the current from an output terminal, comprising: a voltage-current conversion resistor (R1) connected to the first voltage input terminal; and a current mirror circuit which is configured to mirror a current supplied from the voltage-current conversion resistor, wherein the current mirror circuit comprises first N-channel depletion-type transistor (M1) a source voltage of which is biased higher than substrate voltage, a second N-channel depletion-type transistor (M2), a first bias resistor (R2) and a second bias resistor (R4), wherein the voltage-current conversion resistor (R1) has one end connected to the first voltage input terminal and the other end connected to a drain and a gate of the first depletion-type transistor (M1), the first N-channel depletion-type transistor (M1) has a substrate connected to a second voltage input terminal and a source connected to one end of the first bias resistor (R2), the other end of the first bias resistor (R2) is connected to the second voltage input terminal, the second N-channel depletion-type transistor (M2) has a gate connected to the gate and drain of the first N-channel depletion-type transistor (M1), a source connected to one end of the second bias resistor (R4), and a substrate connected to the second voltage input terminal, a drain connected to the output terminal through a load resistor (R3) such that the current flowing through the load resistor (R3) becomes the current output from the output terminal, and the other end of the second bias resistor (R4) is connected to the second voltage input terminal. a voltage-current conversion resistor (R1) connected to the first voltage input terminal; and a current mirror circuit which is configured to mirror a current supplied from the voltage-current conversion resistor, wherein the current mirror circuit comprises first N-channel depletion-type transistor (M1) a source voltage of which is biased higher than substrate voltage, a second N-channel depletion-type transistor (M2), a first bias resistor (R2) and a second bias resistor (R4), wherein the voltage-current conversion resistor (R1) has one end connected to the first voltage input terminal and the other end connected to a drain and a gate of the first depletion-type transistor (M1), the first N-channel depletion-type transistor (M1) has a substrate connected to a second voltage input terminal and a source connected to one end of the first bias resistor (R2), the other end of the first bias resistor (R2) is connected to the second voltage input terminal, the second N-channel depletion-type transistor (M2) has a gate connected to the gate and drain of the first N-channel depletion-type transistor (M1), a source connected to one end of the second bias resistor (R4), and a substrate connected to the second voltage input terminal, a drain connected to the output terminal through a load resistor (R3) such that the current flowing through the load resistor (R3) becomes the current output from the output terminal, and the other end of the second bias resistor (R4) is connected to the second voltage input terminal. <EOS>