An arithmetic circuit for quantizing pre-quantized data includes a first input register to store first-format pre-quantized data that includes a mantissa and an exponent, a second input register to store a quantization target exponent, an exponent-correction-value indicating unit to indicate an exponent correction value, an exponent generating unit to generate a quantized exponent obtained by subtracting the exponent correction value from the quantization target exponent, a shift amount generating unit to generate a shift amount obtained by subtracting the exponent of the pre-quantized data and the exponent correction value from the quantization target exponent, a shift unit to generate a quantized mantissa obtained by shifting the mantissa of the pre-quantized data by the shift amount generated by the shift amount generating unit, and an output register to store quantized data that includes the quantized exponent generated by the exponent generating unit and the quantized mantissa generated by the shift unit.