A valve element of a fuel injection valve comprises a cylindrical structural base which has an upper end contactable with a lower end of a core tube installed in a cylindrical case and a spherical valve head which is contactable with a valve seat arranged at a lower end of the cylindrical case. The outer radius of the orbital portion of the inner rings of two rolling bearings disposed at both axial sides of the cage are designed to be larger than the inner radius of the cage, so that the axial movement of the cage is constrained. Plural floating-island insulators are provided for the resistance heat detector and within wiring thereof. The body also includes an aperture which may be moved to an open position by squeezing or moving a portion of the body, and moved to a closed position by releasing a portion of the body.