In a conventional art, an output layer set having no output layer is sometimes defined. Consequently, even if the decoder decodes a bit stream to obtain each layer in the output layer set without the output layer, there is no picture to be outputted. There is a possibility that such coded data causes the decoder expecting an output to operate unexpectedly. Output layer sets having the same configuration may be defined. Consequently, the amount of code pertaining to the output layer sets defined in an overlapping manner is redundant. According to an aspect of the present invention, specification of a bit stream conformance pertaining to the output layer set prevents occurrence of an output layer set without an output layer and a redundant output layer set.