An image coding apparatus includes a first coding unit that discretely selects quantization parameters of a first range to perform calculation of generated code amounts corresponding to the selected quantization parameters, a second coding unit that performs calculation of generated code amounts corresponding to quantization parameters of a second range, a code amount control unit that decides deciding a temporary quantization parameter corresponding to a target code amount by calculating generated code amounts through an interpolation process for quantization parameters not selected by the first coding unit, and by comparing the generated code amounts corresponding to the selected quantization parameters and the generated code amounts calculated through the interpolation process with the target code amount, and decides an optimal quantization parameter corresponding to the target code amount by comparing the generated code amounts calculated by the second coding unit with the target code amount.