A satellite radio-controlled watch, comprising: a receiving unit for receiving a satellite radio wave containing time information and position information; a storage unit configured to store a) first intersection point information indicating a position of a first intersection point between a first reference line along a line orthogonal to the equator and a time zone boundary not extending along a line of longitude, b) second intersection point information indicating a position of a second intersection point between the time zone boundary and a second reference line along a line orthogonal to the equator and adjacent to the first reference line, and c) time difference division information on a wedge-shaped or belt-shaped area that is adjacent to the first and second reference lines (72, 73) and to which the first intersection point belongs, wherein the area is defined by said first and second reference lines (72, 73) and a line connecting the first intersection point and the second intersection point, or wherein the area is defined by said first and second reference lines (72, 73) and a line orthogonal to the reference lines passing through the first intersection points; and a time zone determination unit for determining a time zone, based on the position information, the first intersection point information, and the time difference division information. a receiving unit for receiving a satellite radio wave containing time information and position information; a storage unit configured to store a) first intersection point information indicating a position of a first intersection point between a first reference line along a line orthogonal to the equator and a time zone boundary not extending along a line of longitude, b) second intersection point information indicating a position of a second intersection point between the time zone boundary and a second reference line along a line orthogonal to the equator and adjacent to the first reference line, and c) time difference division information on a wedge-shaped or belt-shaped area that is adjacent to the first and second reference lines (72, 73) and to which the first intersection point belongs, wherein the area is defined by said first and second reference lines (72, 73) and a line connecting the first intersection point and the second intersection point, or wherein the area is defined by said first and second reference lines (72, 73) and a line orthogonal to the reference lines passing through the first intersection points; a) first intersection point information indicating a position of a first intersection point between a first reference line along a line orthogonal to the equator and a time zone boundary not extending along a line of longitude, b) second intersection point information indicating a position of a second intersection point between the time zone boundary and a second reference line along a line orthogonal to the equator and adjacent to the first reference line, and c) time difference division information on a wedge-shaped or belt-shaped area that is adjacent to the first and second reference lines (72, 73) and to which the first intersection point belongs, wherein the area is defined by said first and second reference lines (72, 73) and a line connecting the first intersection point and the second intersection point, or wherein the area is defined by said first and second reference lines (72, 73) and a line orthogonal to the reference lines passing through the first intersection points; and a time zone determination unit for determining a time zone, based on the position information, the first intersection point information, and the time difference division information.