The invention provides a method for producing methacrylyl-CoA that converts 3-hydroxyisobutyryl-CoA into methacrylyl-CoA using an enzyme having dehydratase activity as a method for producing methacrylyl-CoA using an enzyme catalyst. In this production method, conversion rate of 3-hydroxyisobutyryl-CoA into methacrylyl-CoA by the enzyme having dehydratase activity is 50% or higher. In this production method, furthermore, the enzyme having dehydratase activity derives from a microorganism belonging to the genus Pseudomonas or Rhodococcus.