A secondary battery charging system includes a secondary battery charging device and a power generation device that generates a charging current. The secondary battery charging device controls the charging a secondary battery, which has a protection timer that counts a first elapsed time from a start of charging. The secondary battery charging device includes a charging switch that controls a supply of the charging current, a time management timer portion that counts a second elapsed time starting from a point at which the charging switch becomes conductive and performs a charging stop determination and that counts a third elapsed time starting from a point at which the charging switch is cut off and performs a charging start determination, and a charging control portion that causes the charging switch to be conductive or cut off based on results of the charging stop determination and the charging start determination.