Resin composition for optical waveguides, dry film for optical waveguides, and optical waveguide

A resin composition for use in optical waveguides, the resin composition containing an epoxy resin (A), a (meth)acylate resin (B), and a photopolymerization initiator (C),

• the (meth)acrylate resin (B) including:
• a first (meth)acrylate compound (B-1) having a structural unit expressed by the following formula (1) and a structural unit expressed by the following formula (2);
• and a second (meth)acrylate compound (B-2) different from the first (meth)acrylate compound (B-1),
• content of the first (meth)acrylate compound (B-1) being equal to or greater than 5% by mass and equal to or less than 20% by mass with respect to an entire mass of the epoxy resin (A) and the (meth)acrylate resin (B), and
• content of the second (meth)acrylate compound (B-2) being equal to or greater than 30% by mass and equal to or less than 80% by mass with respect to the entire mass of the epoxy resin (A) and the (meth)acrylate resin (B),
• where in formulae (1) and (2), R1 to R3 are each independently an alkyl group having 1 to 3 carbon atoms or a hydrogen atom, and R4 is an acryloyl group or a methacryloyl group.