Thermosetting resin composition, prepreg, and fiber-reinforced composite material and production method therefor

A thermosetting resin composition comprising:

• an epoxy resin;
• an epoxy resin curing agent;
• an imidazole compound;
• and
• an epoxy resin curing accelerator,
• wherein the epoxy resin curing agent comprises dicyandiamide or a derivative thereof,
• the epoxy resin curing accelerator comprises a urea derivative having two or more dimethylureido groups in a molecule,
• the thermosetting resin composition comprises 1 to 9 parts by mass of the dicyandiamide or a derivative thereof, 1 to 8 parts by mass of the imidazole compound, and 1 to 8 parts by mass of the urea derivative having two or more dimethylureido groups in a molecule, each with respect to 100 parts by mass of the epoxy resin, and
• the epoxy resin comprises 30 to 70 parts by mass of a first epoxy resin having a structure represented by Formula (1) in a molecule, and 20 to 40 parts by mass of a second epoxy resin, each relative to 100 parts by mass of the epoxy resin,
• wherein the second epoxy resin is a polyfunctional epoxy resin having three or more epoxy groups in a molecule, and the polyfunctional epoxy resin does not contain the structure represented by Formula (1).