A sheet heating apparatus include a first heating plate, a second heating plate, a joining member, a heating section, and a guide member. The first heating plate has a first heating surface curved in a convex shape. The second heating plate has a second heating surface curved in a convex shape. The joining member integrally joins the first heating plate and the second heating plate together such that the first heating surface and the second heating surface face outward. The heating section heats the first heating plate and the second heating plate. The guide member guides a sheet such that the sheet comes into contact with the first heating surface and the second heating surface.