Provided is a resin pedal arm of which strength is further improved. A resin pedal arm 10 includes a hollow arm body 20. The arm body 20 includes a front wall portion 30, a rear wall portion 32 facing the front wall portion 30, a left wall portion 34 formed between left edges 30A, 32A of the front wall portion 30 and the rear wall portion 32 and having multiple first flat plate portions 38 arranged to bridge between the left edges 30A, 32A, and a right wall portion 36 formed between right edges 30B, 32B of the front wall portion 30 and the rear wall portion 32, having multiple second flat plate portions 40 arranged to bridge between the right edges 30B, 32B, and facing the left wall portion 34. The multiple second flat plate portions 40 are each present in multiple left opening areas S1 each provided between adjacent ones of the multiple first flat plate portions 38, as viewed in a direction in which the left wall portion 34 and the right wall portion 36 face each other.