Patent ID: 7509741

Claim:
A rotary type electric shaver comprising: a shaver main body: an outer cutter housing provided on said shaver main body; a cutter unit comprised of an outer cutter provided in said outer cutter housing, said outer cutter having a circular top portion with a plurality of slit-shaped hair introduction openings extending in substantially a radial direction formed therein: and an inner cutter disposed inside said outer cutter and rotationally driven by a motor provided inside said shaver main body: wherein the outer cutter is formed with a ring-shaped groove, which is formed in said top portion and concentric wit a center axis line that forms a rotational center of said inner cutter, and two ring-shaped inner cutter running tracks, which are formed in an interior surface of said outer cutter so as to be concentric with said center axis line and on both sides of said ring-shaped groove. said inner cutter is provided with a plurality of cutter blades that make sliding contact with track surfaces of said inner cutter running tracks, a sliding surface defined by said track surfaces of said inner cutter tracks and said cutter blades of said inner cutter is positioned on an plane perpendicular to said center axis line, and a thickness of at least a portion of each of said two ring-shaped inner cutter running tracks from near said ring-shaped groove in said top potion of said outer cutter to an inner and an outer circumferential portion of said top portion for at least part of a circumferential direction of said outer cutter varies; and wherein said portions of said two ring-shaped inner cutter running tracks near said ring-shaped groove are larger in thickness than said circumferential portions.