Superconducting resistive transition in mesoscopic Al ring, disk, and wire samples is reported. In the ring sample, a periodic sharp peak structure, Little–Parks (LP) oscillation, is clearly observed as a function of magnetic field down to 40mK. The oscillation period of about 56G agrees with the value estimated from the sample size. The peak structure is also found in both of the disk and the wire samples. The peaks in the disk sample are qualitatively explained in the framework of the linearized Ginzburg–Landau theory, but those in the wire sample are not understood by the present theory. In all the samples, anomalous negative magnetoresistance is observed at low fields, which may be ascribed to normal superconducting junctions at the nodes.