An encoding device 100 includes a quantization parameter generating circuit 111 that generates a provisional quantization parameter, a quantizing circuit 121 that generates quantized data by quantizing a signal to be quantized on the basis of the provisional quantization parameter, a binarizing circuit 131 that binarizes the quantized data to output binary symbol data, an arithmetic coding circuit 141 that generates coded data by arithmetic-coding the binary symbol data, a quantization parameter calculating circuit 112 that generates a suitable quantization parameter on the basis of a symbol amount of the binary symbol data, a code amount of the coded data, an upper limit of the symbol amount, and an target code amount, a quantizing circuit 122 that quantizes the signal to be quantized on the basis of the suitable quantization parameter.