The attack is the latest to take place in the run-up to presidential elections on April 5.
No group immediately claimed responsibility for the attack in Maymana, the capital of Faryab province, but it happened in an area where the Taliban and allied militant groups are active.
The Taliban have threatened a campaign of violence to disrupt the vote, which will choose a new president to lead the country as foreign troops prepare to end their combat mission by the end of the year.
The attacker was approaching a checkpoint where cars were being searched on a road leading to the governor's compound in Maymana when he detonated explosives hidden in the rickshaw.
Most of the victims were vendors selling bread and other people in the busy roadside market area.
Deputy Governor Abdul Satar Barez said 15 people were killed and 46 others injured, 27 of them seriously, in the explosion which struck some 200 yards from the governor's compound.
Women, children and employees of the nearby electricity department were among the casualties.
Mr Barez said: "They killed innocent people in a place where locals were just trying to earn 10 Afghanis (about 10p) to buy a piece of bread."
The Taliban have staged numerous attacks in Faryab. In October 2012, a suicide bomber struck at a mosque packed with officials in Maymana, killing 41 people.
The UN said 2959 civilians were killed last year.