To provide a motor drive circuit for a coder reader, capable of reducing the influence of dispersion of semiconductor processes and allowed to be formed as an IC by the process of a bipolar transistor.

This code reader, having a motor for scanning a code with laser light and capable of reading out data recorded in the code by irradiating the code with a scanning laser light, is provided with a motor drive circuit 7 constituted of an amplifier stage 21 for amplifying a detection signal from a detection coil 15 of a motor 3, a gain control voltage generation circuit 22, a gain control amplifier 23, and a voltage/current conversion circuit 24 for generating a motor drive signal by VI converting an output from the amplifier 23 and capable of controlling the laser scanning angle at a fixed angle. The amplifier 23 is constituted of a voltage-controlled type current source 31 and a multiplication circuit 32 and an output from the circuit 32 is expressed by a result of mutually multiplying the output value of the current source 31, an output value from the amplification stage 21, a coefficient, and the resistance value of a register formed in the circuit 32.