An encoder (100) includes: circuitry and memory coupled to the circuitry. In the encoder (100), in operation, the circuitry: upon generating an encoded bitstream that includes a multi-layer structure, when it is allowed to arbitrarily specify by a decoder a layer to be output by the decoder, sets a syntax element for specifying a layer that is allowed to be output by the decoder, to a value indicating that it is allowed to arbitrarily specify the layer to be output; and generates the encoded bitstream that includes the multi-layer structure.