A transmission comprising: a clutch configured to transmit or interrupt an engine torque; a transmission mechanism including a main shaft connected to the clutch; main shaft gears corresponding to first to Nth speeds (where N is a natural number equal to or greater than 2) provided on the main shaft; drive shaft gears corresponding to the first to Nth speeds intermeshing with the main shaft gears for the first to Nth speeds, respectively; a drive shaft provided with the drive shaft gears; and a movable gear provided on the main shaft or the drive shaft so as to be movable in an axial direction of the main shaft or the drive shaft; and in which a dog portion is provided on a lateral surface of the movable gear and a dog portion, engageable with the dog portion of the movable gear, is provided on a lateral surface of at least one of the main shaft gears; and/or a dog portion is provided on the lateral surface of the movable gear and a dog portion, engageable with the dog portion of the movable gear, is provided on a lateral surface of at least one of the drive shaft gears; a clutch actuator configured to cause the clutch to be disengaged and engaged; a shift actuator configured to axially move the movable gear; a delay time setting device programmed and configured to set a delay time (T x) which is a time period between a start of disengagement of the clutch and a start of movement of the movable gear; and an actuator controller programmed and configured to control the clutch actuator and the shift actuator so that the movement of the movable gear is started after a lapse of the delay time (T x), set by the delay time setting device, from the start of disengagement of the clutch; characterised in that the delay time setting device is programmed and configured to set the delay time (T x) to a first delay time when an engagement force between dog portions (58, 61) which are to be disengaged from each other by the movement of the movable gear is a first engagement force, and to set the delay time (T x) to a second delay time shorter than the first delay time when the engagement force between the dog portions (58, 61) which are to be disengaged from each other by the movement of the movable gear is a second engagement force smaller than the first engagement force. a clutch configured to transmit or interrupt an engine torque; a transmission mechanism including a main shaft connected to the clutch; main shaft gears corresponding to first to Nth speeds (where N is a natural number equal to or greater than 2) provided on the main shaft; drive shaft gears corresponding to the first to Nth speeds intermeshing with the main shaft gears for the first to Nth speeds, respectively; a drive shaft provided with the drive shaft gears; and a movable gear provided on the main shaft or the drive shaft so as to be movable in an axial direction of the main shaft or the drive shaft; and in which a dog portion is provided on a lateral surface of the movable gear and a dog portion, engageable with the dog portion of the movable gear, is provided on a lateral surface of at least one of the main shaft gears; and/or a dog portion is provided on the lateral surface of the movable gear and a dog portion, engageable with the dog portion of the movable gear, is provided on a lateral surface of at least one of the drive shaft gears; a clutch actuator configured to cause the clutch to be disengaged and engaged; a shift actuator configured to axially move the movable gear; a delay time setting device programmed and configured to set a delay time (T x) which is a time period between a start of disengagement of the clutch and a start of movement of the movable gear; and an actuator controller programmed and configured to control the clutch actuator and the shift actuator so that the movement of the movable gear is started after a lapse of the delay time (T x), set by the delay time setting device, from the start of disengagement of the clutch; characterised in that the delay time setting device is programmed and configured to set the delay time (T x) to a first delay time when an engagement force between dog portions (58, 61) which are to be disengaged from each other by the movement of the movable gear is a first engagement force, and to set the delay time (T x) to a second delay time shorter than the first delay time when the engagement force between the dog portions (58, 61) which are to be disengaged from each other by the movement of the movable gear is a second engagement force smaller than the first engagement force.