Inductor core, electronic pen core portion, electronic pen, and input device

An inductor core, comprising:

• a tubular magnetic material body formed of magnetic material,
• the tubular magnetic material body comprising
• an inclined portion comprising an inclined surface which constitutes a peripheral surface of a truncated cone having an outer diameter that increases from one end toward the other end of the tubular magnetic material body;
• and
• a straight trunk portion which is disposed coaxially with the inclined portion, comprises an outer peripheral surface which constitutes a peripheral surface of a cylindrical body extending from the other end toward the one end of the tubular magnetic material body, and is connected with the inclined portion,
• the outer peripheral surface of the straight trunk portion including a region in a vicinity of the other end with an arithmetic mean roughness Ra, the outer peripheral surface of the straight trunk portion including a region in a vicinity of the inclined portion with an arithmetic mean roughness Ra greater than the arithmetic mean roughness Ra of the region in the vicinity of the other end.