A printing apparatus comprising: a printing unit configured to perform printing on a medium; a transport belt which rotationally moves to transport the medium in a transport direction; a first and a second scale portions (75a, 75b) which are provided along the transport direction; a first measuring unit configured to measure a relative moving amount with respect to the first scale portion; a second measuring unit configured to measure a relative moving amount with respect to the second scale portion; a first holding unit which is configured to move integrally with the first scale portion or the first measuring unit, and holds the transport belt on one side from a center of the transport belt in an intersecting direction intersecting with the transport direction to move along with the transport belt; a second holding unit which is configured to move integrally with the second scale portion or the second measuring unit, and holds the transport belt on the other side from the center of the transport belt in the intersecting direction to move along with the transport belt; characterized in that the printing apparatus further comprises a control unit configured to determine whether or not a difference between a first moving amount measured by the first measuring unit and a second moving amount measured by the second measuring unit is equal to or greater than a reference value, wherein, when the number of times that the transport belt transports the medium is n, the control unit is configured to calculate the difference between the first moving amount and the second moving amount, store the difference as an nth moving amount difference, and store the difference between the first moving amount and the second moving amount calculated before storing the nth moving amount difference as an (n-1)th moving amount difference, and wherein the control unit is configured to perform a warning operation in a case where the control unit determines that a variation of the (n-1)th moving amount difference with respect to the nth moving amount difference is equal to or greater than a reference value. a printing unit configured to perform printing on a medium; a transport belt which rotationally moves to transport the medium in a transport direction; a first and a second scale portions (75a, 75b) which are provided along the transport direction; a first measuring unit configured to measure a relative moving amount with respect to the first scale portion; a second measuring unit configured to measure a relative moving amount with respect to the second scale portion; a first holding unit which is configured to move integrally with the first scale portion or the first measuring unit, and holds the transport belt on one side from a center of the transport belt in an intersecting direction intersecting with the transport direction to move along with the transport belt; a second holding unit which is configured to move integrally with the second scale portion or the second measuring unit, and holds the transport belt on the other side from the center of the transport belt in the intersecting direction to move along with the transport belt; characterized in that the printing apparatus further comprises a control unit configured to determine whether or not a difference between a first moving amount measured by the first measuring unit and a second moving amount measured by the second measuring unit is equal to or greater than a reference value, wherein, when the number of times that the transport belt transports the medium is n, the control unit is configured to calculate the difference between the first moving amount and the second moving amount, store the difference as an nth moving amount difference, and store the difference between the first moving amount and the second moving amount calculated before storing the nth moving amount difference as an (n-1)th moving amount difference, and wherein the control unit is configured to perform a warning operation in a case where the control unit determines that a variation of the (n-1)th moving amount difference with respect to the nth moving amount difference is equal to or greater than a reference value.