To provide a spring unit which is downsized thereby can support a high load, and a slide mechanism.

A spring unit comprises a resin spring 11 which is formed with resin to have a solid beam structure and has a curved part 11a between a pair of end parts 11c and 11d and a metal spring 12 which is formed from a metal wire and has a curved part 12a between a pair of end parts 12c and 12d. It is structured such that end parts 11c and 11d of the resin spring 11 and end parts 12c and 12d of the metal spring 12 are fixed and that the resin spring 11 and the metal spring 12 are located on the same plane when in a fixed state. An engagement part 15, where the resin spring 11 and the metal spring 12 are engaged, is formed in at least one point between the curved parts 11a and 12a and the end parts 11c, 11d, 12c and 12d. The resin spring 11 and the metal spring 12 are separated from each other at regions except the end parts 11c, 11d, 12c and 12d, and the engagement part 15.