A prepreg comprising an epoxy resin composition and reinforcing fiber, the epoxy resin composition comprising an epoxy resin as component, an aromatic urea and/or an imidazole compound as component, and a borate ester compound as component, containing dicyandiamide in the amount of 0.5 part by mass or less relative to the total quantity of epoxy resins, which accounts for 100 parts by mass, and meeting the requirement <i> or <ii> given below: <i> meeting the condition (a), condition (b), and condition (c) given below, <ii> meeting the condition (d) and condition (e) given below, (a) an isocyanurate type epoxy resin is contained as component in an amount of 10 to 40 parts by mass relative to the total quantity of epoxy resins which represents 100 parts by mass, (b) an bisphenol type epoxy resin is contained as component in an amount of 40 to 90 parts by mass relative to the total quantity of epoxy resins which represents 100 parts by mass, (c) resin has an average epoxy equivalent weight of 220 to 500 g/eq, and (d) an epoxy resin as represented by general formula is contained as component in an amount of 50 to 100 parts by mass relative to the total quantity of epoxy resins which represents 100 parts by mass, wherein R 1, R 2, and R 3 are each a hydrogen atom or a methyl group, and n is an integer of 1 or more, and (e) the average epoxy equivalent weight over all epoxy resins is 165 to 265 g/eq. <i> meeting the condition (a), condition (b), and condition (c) given below, <ii> meeting the condition (d) and condition (e) given below, (a) an isocyanurate type epoxy resin is contained as component in an amount of 10 to 40 parts by mass relative to the total quantity of epoxy resins which represents 100 parts by mass, (b) an bisphenol type epoxy resin is contained as component in an amount of 40 to 90 parts by mass relative to the total quantity of epoxy resins which represents 100 parts by mass, (c) resin has an average epoxy equivalent weight of 220 to 500 g/eq, and (d) an epoxy resin as represented by general formula is contained as component in an amount of 50 to 100 parts by mass relative to the total quantity of epoxy resins which represents 100 parts by mass, wherein R 1, R 2, and R 3 are each a hydrogen atom or a methyl group, and n is an integer of 1 or more, and (e) the average epoxy equivalent weight over all epoxy resins is 165 to 265 g/eq. (a) an isocyanurate type epoxy resin is contained as component in an amount of 10 to 40 parts by mass relative to the total quantity of epoxy resins which represents 100 parts by mass, (b) an bisphenol type epoxy resin is contained as component in an amount of 40 to 90 parts by mass relative to the total quantity of epoxy resins which represents 100 parts by mass, (c) resin has an average epoxy equivalent weight of 220 to 500 g/eq, and (d) an epoxy resin as represented by general formula is contained as component in an amount of 50 to 100 parts by mass relative to the total quantity of epoxy resins which represents 100 parts by mass, wherein R 1, R 2, and R 3 are each a hydrogen atom or a methyl group, and n is an integer of 1 or more, and (e) the average epoxy equivalent weight over all epoxy resins is 165 to 265 g/eq.