Dhanera judicial magistrate, first class, V S Thakor, sent Darji to jail, rejecting police's prayer for his four-day remand, additional public prosecutor Prakash Joshi said.
The judge also rejected the bail application of the accused, Mr Joshi said.
The Gujarat police has, meanwhile, launched a manhunt for three more persons allegedly involved in the attack. Police had arrested Darji after some local Congress workers identified him as the one who threw a concrete brick at the vehicle.
The opposition party members also claimed three more people were involved in the conspiracy to attack the Congress leader's vehicle. They have been identified as Bhagwandas Patel, Mor Singh Rao and Mukesh Thakkar.
Police said the three accused are absconding and efforts are on to apprehend them.
The police had yesterday arrested Darji, an office-bearer of the BJP's youth wing in Banaskantha, after his name cropped up during investigation, an official said.
Mr Gandhi, who was on a visit to the flood-affected Dhanera town in Banaskantha district in Gujarat on Friday, escaped unhurt after a brick was thrown at his car.
He had to cut short his address to a gathering in the Lal Chowk area of Dhanera after black flags were shown to him by some of those who turned up for the meeting.
The state government had claimed that Mr Gandhi had not taken the bullet-proof vehicle provided to him and instead decided to travel in the car of a party worker.
Mr Darji and three others have been booked under IPC sections relating to voluntarily causing hurt to deter a public servant from discharging his duty, causing hurt by act endangering life, and mischief causing damage to property".
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)