According to one aspect of the present invention, a sliding member includes: a sliding surface against which an outer surface of a cam abuts; and a groove having a spiral shape or a plurality of grooves having an annular shape, which are provided on the sliding surface. The sliding surface includes a central region having a circular shape and including a center of the sliding surface, and a first annular region located outside the central region. A ratio R C of a width L2 of the groove to a pitch L1 of the groove in the central region is larger than a ratio R O1 of the width L2 of the groove to the pitch L1 of the groove in the first annular region.