Portable apparatus having a slide mechanism for an upper casing and a lower casing

A portable apparatus, having a slide mechanism by which an upper casing can be made to slide with respect to a lower casing, said apparatus comprising:

• an assist mechanism, disposed between said upper casing and said lower casing, and assisting sliding of said upper casing, wherein
• said assist mechanism comprises:
• a first support member attached pivotably to said upper casing or to a member that is fixed to said upper casing;
• a second support member attached pivotably to said lower casing or to a member that is fixed to said lower casing;
• one or a plurality of first elastic springs that bias said first support member;
• one or a plurality of second elastic springs that bias said second support member;
• and
• a holding case that holds said first elastic spring(s) and said second elastic spring(s) in a serially arrayed state with a direction of extension and contraction of said first elastic spring(s) forming a prescribed angle to a direction of extension and contraction of said second elastic spring(s), said first support member being slidably inserted in the direction of extension and contraction of said first elastic spring(s), and said second support member being slidably inserted in the direction of extension and contraction of said second elastic spring(s).