By completing curing in a short period of time even at low temperatures and using an epoxy resin composition as a matrix resin of a prepreg, it is possible to obtain a fiber-reinforced composite plastic product such as a fiber-reinforced tubular composite with excellent mechanical properties and, more particularly, excellent impact resistance. The epoxy resin composition includes A component, B component, C component, D component and E component, where the content rate of sulfur atoms is equal to or more than 0.2 wt % and equal to or less than 7 wt %, and the content rate of the C component is equal to or more than 1 wt % and equal to or less than 15 wt %. A component: epoxy resins, B component: reactive products of the epoxy resins and an amine compounds including the sulfur atom in a molecule (the unreacted epoxy resins and/or the amine compounds may be included), C component: polyamide compounds soluble in the A component, D component: urea compounds, and E component: dicyandiamide.