To provide a self adjusting seal head assembly which can keep stable seal surface contactness under any operation condition, irrespective of lubrication of a seal surface, eccentricity, and shaft run-out.

A self adjusting seal device has a spring sheet 32 having elasticity, an elastic boot 22 being in contact with the spring sheet 32, and a fixed housing. The boot 22 has a ferrule 28 formed thereinside. The self-adjusting seal device also has a seal sheet assembly including a circular seal sheet made of ceramic material, and a seal washer being in contact with the seal sheet assembly.