Bicycle crank fixing structure

A bicycle crank fixing structure (56) is arranged to fix a left crank (52) with a mounting bore (52a) and a slit (52d) extending radially from the mounting bore (52a) to a crank axle (54). The mounting bore (52a) is non-rotatably coupled to the crank axle (54). The slit (52d) is provided with two mounting bolts that perpendicularly intersect to adjust a width of the slit (52d) to fasten the crank (52) to the crank axle (54). The crank axle (54) has a retaining hole formed on the outer circumferential surface thereof which faces the slit (52d) of the crank (52). A retaining member (58) with a retaining projection (58c) is disposed in the slit (52d) such that the retaining member (58) rotates by rotation of the mounting bolt. The retaining projection (58c) of the retaining member (58) is retained in the retaining hole formed on the crank axle (54) to prevent the crank (52) from detaching from the crank axle (54) even when a fastening bolt (59) is loosened.