A linear motor comprising a stator unit that including a slider having a mover, a motor body disposed in a moving path of the slider, and stators attached to the motor body, the stators being arranged along the moving path such that the stators face the mover, the linear motor being configured to move the slider along the moving path by generating attractive force between the stators and the mover, wherein said stator unit comprises: a plurality of sensor substrates (112A, 112B, 112C, 112D) attached to the motor body so as to correspond to the respective stators, each of the plurality of sensor substrates (112A, 112B, 112C, 112D) is sized within a dimension of the respective stators with respect to a moving direction extending along the moving path; upstream-side position detecting means (SA1, SB1) attached to each sensor substrate (112A, 112B, 112C, 112D), the upstream-side position detecting means (SA1, SB1) being configured to detect the slider arriving at an upstream portion of each sensor substrate (112A, 112B, 112C, 112D) in the moving direction and output a position detection signal; and downstream-side position detecting means (SA2, SB2) attached to each sensor substrate (112A, 112B, 112C, 112D), the downstream-side position detecting means (SA2, SB2) being configured to detect the slider arriving at a downstream portion of each sensor substrate (112A, 112B, 112C, 112D) in the moving direction and output a position detection signal; characterized in that said stator unit further comprises: a position detection signal adding unit attached to each sensor substrate (112A, 112B, 112C, 112D), the position detection signal adding unit being configured to add one position detection signal from the downstream-side position detecting means (SA2, SB2) of a sensor substrate being adjacent to an upstream side of the one sensor substrate in the moving direction and the position detection signal from the upstream-side position detecting means (SA1, SB1) of a sensor substrate being adjacent to a downstream side of the one sensor substrate in the moving direction to obtain an addition signal, and the position detection signal adding unit being capable of outputting the addition signal; and a control device configured to detect a position of the slider relative to one stator to which the one sensor substrate corresponds, based on the addition signal from the position detection signal adding unit. a plurality of sensor substrates (112A, 112B, 112C, 112D) attached to the motor body so as to correspond to the respective stators, each of the plurality of sensor substrates (112A, 112B, 112C, 112D) is sized within a dimension of the respective stators with respect to a moving direction extending along the moving path; upstream-side position detecting means (SA1, SB1) attached to each sensor substrate (112A, 112B, 112C, 112D), the upstream-side position detecting means (SA1, SB1) being configured to detect the slider arriving at an upstream portion of each sensor substrate (112A, 112B, 112C, 112D) in the moving direction and output a position detection signal; and downstream-side position detecting means (SA2, SB2) attached to each sensor substrate (112A, 112B, 112C, 112D), the downstream-side position detecting means (SA2, SB2) being configured to detect the slider arriving at a downstream portion of each sensor substrate (112A, 112B, 112C, 112D) in the moving direction and output a position detection signal; characterized in that said stator unit further comprises: a position detection signal adding unit attached to each sensor substrate (112A, 112B, 112C, 112D), the position detection signal adding unit being configured to add one position detection signal from the downstream-side position detecting means (SA2, SB2) of a sensor substrate being adjacent to an upstream side of the one sensor substrate in the moving direction and the position detection signal from the upstream-side position detecting means (SA1, SB1) of a sensor substrate being adjacent to a downstream side of the one sensor substrate in the moving direction to obtain an addition signal, and the position detection signal adding unit being capable of outputting the addition signal; and a control device configured to detect a position of the slider relative to one stator to which the one sensor substrate corresponds, based on the addition signal from the position detection signal adding unit. a position detection signal adding unit attached to each sensor substrate (112A, 112B, 112C, 112D), the position detection signal adding unit being configured to add one position detection signal from the downstream-side position detecting means (SA2, SB2) of a sensor substrate being adjacent to an upstream side of the one sensor substrate in the moving direction and the position detection signal from the upstream-side position detecting means (SA1, SB1) of a sensor substrate being adjacent to a downstream side of the one sensor substrate in the moving direction to obtain an addition signal, and the position detection signal adding unit being capable of outputting the addition signal; and a control device configured to detect a position of the slider relative to one stator to which the one sensor substrate corresponds, based on the addition signal from the position detection signal adding unit.