Base material processing apparatus and detection method

A base material processing apparatus comprising:

• a transport mechanism that transports a long band-like base material in a longitudinal direction along a predetermined transport path;
• a first detection part that acquires a first detection result by continuously or intermittently detecting a position of an edge of the base material in a width direction at a first detection position in said transport path;
• a second detection part that acquires a second detection result by continuously or intermittently detecting a position of the edge of the base material in the width direction at a second detection position that is located downstream of said first detection position in said transport path;
• and
• a displacement amount calculation part that calculates an amount of expansion and contraction of the base material in the width direction on the basis of said first detection result and said second detection result and calculates an amount of displacement in a position of the base material in a transport direction on the basis of a result that is obtained by substituting a calculation result of the amount of expansion and contraction of said base material in the width direction into a matrix transformation that expresses a relationship between the amount of expansion and contraction of the base material in the width direction and an amount of expansion and contraction of the base material in the transport direction.