PURPOSE: To obtain the title hat unit having large impact absorbing capacity and simultaneously capable of exhibiting excellent buffer function also to light impact force by forming at least part of impact absorbing liner fitted in a shell into plural-layer structure.

CONSTITUTION: A doom-shaped impact absorbing liner 3 fitted in the inside of a doom-shaped shell 2 is composed of a main liner 4 of relatively low density having a recessed part 4a in the outer face of front head part and subsidiary liner 5 having relatively high density, packing the recessed part 4a and bonded with the main liner 4. By the above-mentioned construction, impact absorbing capacity and wearing feeling can be simultaneously satisfied.