A transmit apparatus for transmitting data by modulation schemes that shift amplitude and phase, the transmit apparatus comprising: a selector that selects a first modulation scheme or a second modulation scheme for each symbol in a symbol sequence generated from bit sequence encoded by using error correction coding scheme, alternating between the first modulation scheme and the second modulation scheme, the first modulation scheme having same number of constellation points as the second modulation scheme, a constellation and bit labelling of each constellation point of the first modulation scheme being different to a constellation and bit labelling of each constellation point of the second modulation scheme; a mapper that performs mapping by using constellation points of a selected modulation scheme; and a transmitter that transmits a modulated signal obtained by the mapping, wherein the first modulation scheme is a modulation scheme in which a defined number of constellation points are arranged on each circumference of a plurality of concentric circles having different radii on an I-Q plane, the second modulation scheme is an APSK modulation scheme in which a defined number of constellation points are arranged on each circumference of a plurality of concentric circles having different radii on an I-Q plane, characterised in that a sequence of numbers of constellation points on each circumference of the plurality of concentric circles according to the first modulation scheme, in order from the circle with the largest circumference, is different from a sequence of numbers of constellation points on each circumference of the plurality of concentric circles according to the second modulation scheme. a selector that selects a first modulation scheme or a second modulation scheme for each symbol in a symbol sequence generated from bit sequence encoded by using error correction coding scheme, alternating between the first modulation scheme and the second modulation scheme, the first modulation scheme having same number of constellation points as the second modulation scheme, a constellation and bit labelling of each constellation point of the first modulation scheme being different to a constellation and bit labelling of each constellation point of the second modulation scheme; a mapper that performs mapping by using constellation points of a selected modulation scheme; and a transmitter that transmits a modulated signal obtained by the mapping, wherein the first modulation scheme is a modulation scheme in which a defined number of constellation points are arranged on each circumference of a plurality of concentric circles having different radii on an I-Q plane, the second modulation scheme is an APSK modulation scheme in which a defined number of constellation points are arranged on each circumference of a plurality of concentric circles having different radii on an I-Q plane, characterised in that a sequence of numbers of constellation points on each circumference of the plurality of concentric circles according to the first modulation scheme, in order from the circle with the largest circumference, is different from a sequence of numbers of constellation points on each circumference of the plurality of concentric circles according to the second modulation scheme.