Tommy Sheppard said the party needs an “organisational upgrade” after its massive growth in membership.
More than 120,000 people are now members of the SNP, compared with some 25,000 when the vote on independence was held in September 2014.
Mr Sheppard, one of four men vying to succeed Stewart Hosie as depute leader, said the main reason why he is running is to improve the organisation.
He said: “This election isn’t about policy or being left or right. From my point of view the main point of this election, the main point why I am standing, is all about organisation.”