INDUCTOR CORE, ELECTRONIC PEN CORE PORTION, ELECTRONIC PEN, AND INPUT DEVICE

An inductor core includes: a tubular magnetic material body (10) formed of magnetic material. The tubular magnetic material body (10) includes an inclined portion (11) including an inclined surface (11a) which constitutes a peripheral surface of a truncated cone having an outer diameter that increases from one end (10a) toward the other end (10b) of the tubular magnetic material body (10); and a straight trunk portion (12) which is disposed coaxially with the inclined portion (11), includes an outer peripheral surface (12a, 12b) which constitutes a peripheral surface of a cylindrical body extending from the other end (10b) toward the one end (10a) of the tubular magnetic material body, and is connected with the inclined portion (11). An arithmetic mean roughness Ra of a region in the outer peripheral surface (12c) of the straight trunk portion (12) which region is in a vicinity of the other end (10b), is smaller than an arithmetic mean roughness Ra of a region in the outer peripheral surface (12b) of the straight trunk portion (12) which region is in a vicinity of the inclined portion (11).